remove refs to keystone.common.logging

A couple references to this module were missed, and a few new ones were
created while it was in the process of being deprecated. This change
removes outstanding references to the module.

blueprint unified-logging-in-keystone

Change-Id: I4cc7614b3f74caaec9dfa100202d9d6db4ebfc36
Merge "remove refs to keystone.common.logging"