--defaults-file requires datadir to be set.

[James Dooley]

When using a default file with percona-xtrabackup.2.3.2-1.el5 datadir is complaining about being mismatched if it is not specifically set in the defaults file.

innobackupex --defaults-file=/root/.my.cnf --no-timestamp --no-version-check /backup/mysql

Error: option 'datadir' has different values:
  '.' in defaults file
  '/var/lib/mysql/' in SHOW VARIABLES

If the datadir is specified in the .my.cnf file, backups work as intended.

[Sergei Glushchenko (sergei.glushchenko)]

xtrabackup must use datadir received from server if was not set explicitly

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/238748
Committed: https://git.openstack.org/cgit/openstack/openstack-ansible/commit/?id=113597a7cf16c9ae791cc412b2e1a07188b28fd5
Submitter: Jenkins
Branch: master

commit 113597a7cf16c9ae791cc412b2e1a07188b28fd5
Author: Kevin Carter <email address hidden>
Date: Thu Oct 22 21:12:34 2015 -0500

    Pinned percona-xtrabackup to ensure stability

    This change makes it so that the xtrabackup plugin is pinned
    to a specific version via downloading the deb.

    This reinstates the galera affinity values for testing so that
    we're not skipping potentially broken code paths.

    Related-Bug: #1508411
    Related-Bug: #1508448
    Related-Bug: #1508450
    Change-Id: I288d6d9871eb9dfe0ecc547e50639078afdff79d
    Signed-off-by: Kevin Carter <email address hidden>

[Sergei Glushchenko (sergei.glushchenko)]

https://github.com/percona/percona-xtrabackup/pull/140

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PXB-736