Our tests' mocking is a little messy, we have tests that start a mocking
but don't stop it, others try to stop it but use a mock object instead
of a patcher object, so they don't stop it, and we keep using stopall to
stop the patchings instead of individual stops, and we've seen in Cinder
that this can be problematic.
This patch fixes these issue, most of them just by using base TestCase
mock_object method, and some calling the right stop method (ie:
VolumeEncryptorTestCase).
Change-Id: I545abfa8749e778e923c37e0b908efc578f70619
45184cb9b0