test cleanup: Remove skipIf test decorator
test cleanup: Remove skipIf test decorator

We use this from time to time to skip tests for various reasons. It's
not currently in use. But if it's needed, we should use
testtools.testcase.skipIf, which does the same thing, rather than
carrying our own copy around.

Change-Id: I422fe0bc4d761a374daaf0bf1043d5b8fb41d449

openstack/nova,klmitch/nova,rahulunair/nova,klmitch/nova,mahak/nova,openstack/nova,klmitch/nova,klmitch/nova,rahulunair/nova,mahak/nova,rahulunair/nova,openstack/nova,mahak/nova