Comment 10 for bug 1747655

See also https://bugs.launchpad.net/keystonemiddleware/+bug/1749797 where there's also a feeling that the error message could be improved. The client of a service that is using keystonemiddleware needs to know that it is keystone that is causing the 503, not the service they are accessing. Without something in the response body, they can't know.

Restricting that info to just the log doesn't help the client at all and since we cannot predict all the contexts within which the client will operate, we need to be flexible.