Replace using tests.utils part1

It is the second step to replace using tests.utils with
stack.common.test.
In this patch first part of tests is changed for using
openstack.common.test and added needed fixtures in test classes.

Change-Id: Id95743059818a80af5bf1fab4ae1cee528b92809
bp: common-unit-tests
Merge "Replace using tests.utils part1"