Fix publish_errors unit test

The unit test for publish_errors=True causes logging to be spewed from
other tests because it configures the default root logger rather than
creating its own logger like other logging tests do. This makes the unit
tests completely silent again.

Also, it hooked into the rpc notifier to catch notifications when it can
simple hook into the no-op notifier like other tests.

Finally, it used stubout to override the value of config options rather
than the BaseTestCase.config() helper method.

Change-Id: I13313fcd9ad8f9e5bcb9af90652b5dde5c3feec9
Merge "Fix publish_errors unit test"