Remove innodb_version

Until MDEV-16172 was implemented in MariaDB Server 10.3.7, InnoDB used to report a MySQL based version number at startup. Since then, the startup message reported a MariaDB version number, like this:

2022-05-13  8:41:09 0 [Note] InnoDB: 10.6.7 started; log sequence number 0; transaction id 3

That version number was already reported by an earlier message:

2022-05-13  8:41:09 0 [Note] /dev/shm/10.6/sql/mariadbd (server 10.6.7-MariaDB-debug) starting as process 23497 ...

Let us remove the redundant version number from InnoDB startup messages.

Note: At the start of the InnoDB redo log file ib_logfile0 there will continue to be a string that reports the program version with which the log file was created or rebuilt.