Fix retries after authentication failures

Even after #391 and 00739666cd62ed1ff34ae5c5585f479b23e77c80, we're getting this after tokens expire:

    AttributeError: 'CFClient' object has no attribute 'plug_hole_in_swiftclient_auth'

See also this comment: https://github.com/rackspace/pyrax/issues/391#issuecomment-45435433