Use new olso fixture in CM tests

Before this change mox and cfg.CONF wasn't cleaned up correctly if
skipTest is called, because when skipTest is used teardown is not
called.

Now we use the oslo fixtures to setup oslo.config and mox to ensure the
cleanup is done between each tests.

Fixes bug #1211239

Change-Id: I5075c99106742859f0705b765f8ed4aa9be494d7
Merge "Use new olso fixture in CM tests"