Code review comment for lp:~laurynas-biveinis/percona-xtrabackup/bug1098498-1132763-2.0

- I don't understand the reason to call free_reserved_port and reset_server_variables only if the PID file exists in stop_server / shutdown_server. Don't we still want to cleanup in case the PID file disappeared for whatever reasons?

- Was the following change really necessary?

128 -dd if=/dev/zero of=$mysql_datadir/sakila/rental.ibd seek=1000 count=1
129 +printf '\xAA\xAA\xAA\xAA' | dd of=$mysql_datadir/sakila/rental.ibd seek=16384 count=4

- Was the following change really necessary?

215 # also test xtrabackup --stats work with --tables-file
216 -COUNT=`xtrabackup --stats --tables='test.test$' --datadir=$topdir/backup \
217 +COUNT=`xtrabackup --stats --tables='^(mysql.*|performance_schema.*|test.test)$' --datadir=$topdir/backup \