Replace using tests.utils with openstack.common.test
Replace using tests.utils with openstack.common.test

It is the first step to replace using tests.utils with openstack.common.test.
All these tests don't use mock objects, stubs, config files and use only
BaseTestCase class.

Change-Id: I511816b5c9e6c5c34ebff199296ee4fc8b84c672
bp: common-unit-tests

FlaPer87/oslo.text