ceph backup needs to ignore stale snapshots

[Edward Hope-Morley]

I just hit an issue with the following steps:

1. create vol
2. create backup (works fine uses incremental diff)
3. delete backup
4. create new backup (full copy forced because volume backup-snap exists and is not ignored)

The ceph backup driver needs to either (a) ignore the backup snap if the base it was applied to was deleted or (b) delete the backup snap when the backup is deleted if the base is being deleted.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/45480

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/45480
Committed: http://github.com/openstack/cinder/commit/c5060dd0e796ac92ecb2b5d75f9e700509827806
Submitter: Jenkins
Branch: master

commit c5060dd0e796ac92ecb2b5d75f9e700509827806
Author: Edward Hope-Morley <email address hidden>
Date: Fri Sep 6 20:40:38 2013 +0100

    Fixed erroneous force full copy in ceph backup driver

    The following steps should not result in a forced full copy:

    1. create vol
    2. create backup (works fine i.e. uses incremental diff)
    3. delete backup
    4. create new backup (full copy forced because volume backup-snap exists and is not ignored)

    This patch resolves the above problem.

    Change-Id: I61c245219f54f7ee942e06e343c5d79d4cab947b
    Fixes: bug #1221836