Remove references to "xtrabackup" and "innobackupex" executables in mariabackup option descriptions

$ mariabackup --help

...

  -v, --version       print xtrabackup version information

...

  --incremental-history-name=name

                      This option specifies the name of the backup series

                      stored in the PERCONA_SCHEMA.xtrabackup_history history

                      record to base an incremental backup on. Xtrabackup will

                      search the history table looking for the most recent

                      (highest innodb_to_lsn), successful backup in the series

                      and take the to_lsn value to use as the starting lsn for

                      the incremental backup. This will be mutually exclusive

                      with --incremental-history-uuid, --incremental-basedir

                      and --incremental-lsn. If no valid lsn can be found (no

                      series by that name, no successful backups by that name)

                      xtrabackup will return with an error. It is used with the

                      --incremental option.

  --incremental-history-uuid=name

                      This option specifies the UUID of the specific history

                      record stored in the PERCONA_SCHEMA.xtrabackup_history to

                      base an incremental backup on.

                      --incremental-history-name, --incremental-basedir and

                      --incremental-lsn. If no valid lsn can be found (no

                      success record with that uuid) xtrabackup will return

                      with an error. It is used with the --incremental option.

...

  --ftwrl-wait-query-type=name

                      This option specifies which types of queries are allowed

                      to complete before innobackupex will issue the global

                      lock. Default is all.. One of: ALL, UPDATE, SELECT

...

  --kill-long-queries-timeout=#

                      This option specifies the number of seconds innobackupex

                      waits between starting FLUSH TABLES WITH READ LOCK and

                      killing those queries that block it. Default is 0

                      seconds, which means innobackupex will not attempt to

                      kill any queries.

  --ftwrl-wait-timeout=#

                      This option specifies time in seconds that innobackupex

                      should wait for queries that would block FTWRL before

                      running it. If there are still such queries when the

                      timeout expires, innobackupex terminates with an error.

                      Default is 0, in which case innobackupex does not wait

                      for queries to complete and starts FTWRL immediately.

  --ftwrl-wait-threshold=#

                      This option specifies the query run time threshold which

                      is used by innobackupex to detect long-running queries

                      with a non-zero value of --ftwrl-wait-timeout. FTWRL is

                      not started until such long-running queries exist. This

                      option has no effect if --ftwrl-wait-timeout is 0.

                      Default value is 60 seconds.

  --debug-sleep-before-unlock=#

                      This is a debug-only option used by the XtraBackup test

                      suite.

...

  --binlog-info[=name]

                      This option controls how XtraBackup should retrieve

                      server's binary log coordinates corresponding to the

                      backup. Possible values are OFF, ON, LOCKLESS and AUTO.

                      See the XtraBackup manual for more information. One of:

                      off, lockless, on, auto

...

  --debug-sync=name   Debug sync point. This is only used by the xtrabackup

                      test suite

$ mariabackup --innobackupex --help

...

Usage: [--innobackupex [--defaults-file=#] --backup | --innobackupex [--defaults-file=#] --prepare] [OPTIONS]

  -v, --version       print xtrabackup version information

...

  --incremental       This option tells xtrabackup to create an incremental

                      backup, rather than a full one. It is passed to the

                      xtrabackup child process. When this option is specified,

                      either --incremental-lsn or --incremental-basedir can

                      also be given. If neither option is given, option

                      --incremental-basedir is passed to xtrabackup by default,

                      set to the first timestamped backup directory in the

                      backup base directory.

...

  --incremental-history-name=name

                      This option specifies the name of the backup series

                      stored in the PERCONA_SCHEMA.xtrabackup_history history

                      record to base an incremental backup on. Xtrabackup will

                      search the history table looking for the most recent

                      (highest innodb_to_lsn), successful backup in the series

                      and take the to_lsn value to use as the starting lsn for

                      the incremental backup. This will be mutually exclusive

                      with --incremental-history-uuid, --incremental-basedir

                      and --incremental-lsn. If no valid lsn can be found (no

                      series by that name, no successful backups by that name)

                      xtrabackup will return with an error. It is used with the

                      --incremental option.

  --incremental-history-uuid=name

                      This option specifies the UUID of the specific history

                      record stored in the PERCONA_SCHEMA.xtrabackup_history to

                      base an incremental backup on.

                      --incremental-history-name, --incremental-basedir and

                      --incremental-lsn. If no valid lsn can be found (no

                      success record with that uuid) xtrabackup will return

                      with an error. It is used with the --incremental option.

  --ftwrl-wait-query-type=name

                      This option specifies which types of queries are allowed

                      to complete before innobackupex will issue the global

                      lock. Default is all.. One of: ALL, UPDATE, SELECT

...

  --include=name      This option is a regular expression to be matched against

                      table names in databasename.tablename format. It is

                      passed directly to xtrabackup's --tables option. See the

                      xtrabackup documentation for details.

  --databases=name    This option specifies the list of databases that

                      innobackupex should back up. The option accepts a string

                      argument or path to file that contains the list of

                      databases to back up. The list is of the form

                      "databasename1[.table_name1] databasename2[.table_name2]

                      . . .". If this option is not specified, all databases

                      containing MyISAM and InnoDB tables will be backed up.

                      Please make sure that --databases contains all of the

                      InnoDB databases and tables, so that all of the

                      innodb.frm files are also backed up. In case the list is

                      very long, this can be specified in a file, and the full

                      path of the file can be specified instead of the list.

                      (See option --tables-file.)

  --kill-long-queries-timeout=#

                      This option specifies the number of seconds innobackupex

                      waits between starting FLUSH TABLES WITH READ LOCK and

                      killing those queries that block it. Default is 0

                      seconds, which means innobackupex will not attempt to

                      kill any queries.

  --ftwrl-wait-timeout=#

                      This option specifies time in seconds that innobackupex

                      should wait for queries that would block FTWRL before

                      running it. If there are still such queries when the

                      timeout expires, innobackupex terminates with an error.

                      Default is 0, in which case innobackupex does not wait

                      for queries to complete and starts FTWRL immediately.

  --ftwrl-wait-threshold=#

                      This option specifies the query run time threshold which

                      is used by innobackupex to detect long-running queries

                      with a non-zero value of --ftwrl-wait-timeout. FTWRL is

                      not started until such long-running queries exist. This

                      option has no effect if --ftwrl-wait-timeout is 0.

                      Default value is 60 seconds.

  --debug-sleep-before-unlock=#

                      This is a debug-only option used by the XtraBackup test

                      suite.

...

  --compress[=name]   This option instructs xtrabackup to compress backup

                      copies of InnoDB data files. It is passed directly to the

                      xtrabackup child process. Try 'xtrabackup --help' for

                      more details.

  --compress-threads=#

                      This option specifies the number of worker threads that

                      will be used for parallel compression. It is passed

                      directly to the xtrabackup child process. Try 'xtrabackup

                      --help' for more details.

  --compress-chunk-size=#

                      Size of working buffer(s) for compression threads in

                      bytes. The default value is 64K.

  --export            This option is passed directly to xtrabackup's --export

                      option. It enables exporting individual tables for import

                      into another server. See the xtrabackup documentation for

                      details.

  --extra-lsndir=name This option specifies the directory in which to save an

                      extra copy of the "xtrabackup_checkpoints" file. The

                      option accepts a string argument. It is passed directly

                      to xtrabackup's --extra-lsndir option. See the xtrabackup

                      documentation for details.

...

  --parallel=#        On backup, this option specifies the number of threads

                      the xtrabackup child process should use to back up files

                      concurrently.  The option accepts an integer argument. It

                      is passed directly to xtrabackup's --parallel option. See

                      the xtrabackup documentation for details.

  --stream=name       This option specifies the format in which to do the

                      streamed backup.  The option accepts a string argument.

                      The backup will be done to STDOUT in the specified

                      format. Currently, the only supported formats are tar and

                      xbstream. This option is passed directly to xtrabackup's

                      --stream option.

  --tables-file=name  This option specifies the file in which there are a list

                      of names of the form database.  The option accepts a

                      string argument.table, one per line. The option is passed

                      directly to xtrabackup's --tables-file option.

  --throttle=#        This option specifies a number of I/O operations (pairs

                      of read+write) per second.  It accepts an integer

                      argument.  It is passed directly to xtrabackup's

                      --throttle option.

...

  --use-memory=#      This option accepts a string argument that specifies the

                      amount of memory in bytes for xtrabackup to use for crash

                      recovery while preparing a backup. Multiples are

                      supported providing the unit (e.g. 1MB, 1GB). It is used

                      only with the option --apply-log. It is passed directly

                      to xtrabackup's --use-memory option. See the xtrabackup

                      documentation for details.