Comment 2 for bug 1055076

Reviewed: https://review.openstack.org/13541
Committed: http://github.com/openstack/nova/commit/9562ee3ce71301fa0e4de0c167d6cc1cf83ed9a6
Submitter: Jenkins
Branch: master

commit 9562ee3ce71301fa0e4de0c167d6cc1cf83ed9a6
Author: Vishvananda Ishaya <email address hidden>
Date: Sun Sep 23 16:17:35 2012 +0000

    Fixes snapshotting of instances booted from volume

    When an instance was booted from a volume, the block device mapping
    entry has volume_id set. If it was booted from a snapshot it has
    volume_id and snapshot_id set. When we snapshot the instance, it
    should be snapshotting the volume in both cases.

    This patch fixes the faulty logic that was causing snapshotting to
    only happen in the case the instance was booted from a snapshot.

    It also includes a (formerly failing) test to verify that the volume
    commands are actually called and the new snapshot is set properly.

    Fixes bug 1055076

    Change-Id: Icdd2ab7f3e2d43a0564aea132fe707a592fe4e75