CE-2555: Stop test from overwriting production config

When we switched the -test server to allow us to read (but not write) the production configuration, we accidentally made it so that it overwrites some of the production setup on awx. Given that the -test setup should never need to use any of the AWX templates, notifications, etc. etc., it seems simplest to just disallow the test setup from ever modifying AWX's config.

This does mean that the test server could only work after the prod server has been set up. That seems to be an acceptable assumption to work with, however.