Slave backup(with InnoBackupEx) procedure requires additional options

[Denis M.]

Once base replication patchset lands, we would need to improve backuping procedure for InnoBackupEx strategy(see [1]).

We need to add additional attributes, such as:

 --slave-info option, for more info see [2].

 --safe-slave-backup option, for more info see [2].

Another thing we might take into account, see [3].

[1] Command that's being executed against generic Trove instance with mysql datastore:
see https://github.com/openstack/trove/blob/master/trove/guestagent/strategies/backup/mysql_impl.py

[2] xtrabackup CLI parameters:
see http://www.percona.com/doc/percona-xtrabackup/2.1/innobackupex/replication_ibk.html

[3] Advanced replication setup with xtrabackup
see http://www.percona.com/doc/percona-xtrabackup/2.1/howtos/setting_up_replication.html#replication-howto