cinder-backup doesn't use/check metadata version during restore

[stephen mulcahy]

cinder-backup services have a SERVICE_VERSION associated with them which is written to the backup metadata file. This version should be checked during restores to verify that the service is compatible with a particular version a backup. Implementing rudimentary handling of this now will facilitate graceful handling of newer versions if and when the SERVICE_VERSION is incremented.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/23430

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/23430
Committed: http://github.com/openstack/cinder/commit/15962a4d13334b2265120e67ab4222b119e95c3e
Submitter: Jenkins
Branch: master

commit 15962a4d13334b2265120e67ab4222b119e95c3e
Author: Stephen Mulcahy <email address hidden>
Date: Mon Mar 4 16:10:34 2013 +0000

    swift backup service checks version during restore

    Modified swift backup service to check metadata version during restore
    and raise an error if the backup version isn't a version that the
    service knows how to handle. The versions which can be handled are
    described in a dictionary mapping versions to methods which can handle
    them. This will facilitate graceful handling of newer backup formats by
    the swift backup service when we introduce changes.

    Fixes bug: 1136174

    Change-Id: Id7d05848fd448ce21f641e5cd6945477702cbe38