trivial: Mark inner method as such
trivial: Mark inner method as such

Took me a while to figure out this wasn't part of the API for an auth
backend. Make that more obvious.

Change-Id: Idb5efd850426b41d638c6d8c7112735d1423fdab
Signed-off-by: Stephen Finucane <4725dc7f3632bf126d9fbdc30c347e91e8d2fe16@redhat.com>

NeCTAR-RC/horizon,NeCTAR-RC/horizon,openstack/horizon,openstack/horizon,ChameleonCloud/horizon,openstack/horizon,openstack/horizon,NeCTAR-RC/horizon,ChameleonCloud/horizon,ChameleonCloud/horizon,NeCTAR-RC/horizon,ChameleonCloud/horizon