Updated openstack/openstack
Project: openstack/nova  2bb94d7847fbbeddf48b2e7c1767bbd36ead4444

libvirt: convert volume snapshot test case to avoid DB usage

Convert the LibvirtVolumeSnapshotTestCase so that it avoids
creating instance objects in the database. This allows it to
be converted to use NoDBTestCase improving perf from 4.2s
to 2.3s

Partial-bug: #1369516
Change-Id: Idf4d29a0df2280c78fe879fa09632c666ff04436