Use stubout in test_correlation_id
Use stubout in test_correlation_id

Best to use stubout for stubbing out methods like this. That way they
get properly unstubbed on failure.

Change-Id: I61dc96d01e331e8d811b8f24137e8f738cf09215

JioCloud/oslo-incubator,JioCloud/oslo-incubator,JioCloud/oslo-incubator