Deprecate mariadb-find-rows

The tool mysql_find_rows, now updated to mariadb-find-rows, is seriously outdated. The fix to update it to use MariaDB instead of MySQL naming didn't help much, quite the opposite, The help-text says that this tool "is useful to find things in a MariaDB update log". In reality few people even remembers the update log anymore and it has never existed in MariaDB at all and in MySQL it was retired as of MySQL 5.0!