Updated openstack/openstack
Project: openstack/nova  458655f26d097061575798d4f90ed17cdd894768

libvirt: convert CacheConcurrencyTestCase to avoid DB usage

The CacheConcurrencyTestCase test case does not do anything DB
related. Convert it to NoDBTestCase to avoid DB setup penalty.
This improves perf from 1.7s to 0.2s

Partial-bug: #1369516
Change-Id: I8ef124e9f5d86a990722019978c725c955ffb1ea