Remove use of mock CONF object
Remove use of mock CONF object

We shouldn't be using a mock CONF object in tests, instead we
should be using the 'flags' method of the cinder.tests.unit.test.
TestCase class.

See https://review.opendev.org/c/openstack/cinder/+/839793/6 if
you're not sure why.

Change-Id: I100b47697afa9241dad856baef613c687428d6d1

mahak/cinder,openstack/cinder,openstack/cinder,mahak/cinder