Idb0f408776ef27f16a522e4443531fd97276669b switches to use
www_authenticate_uri but it is not backwards incompatible for folks who
have yet to switch to use www_authenticate_uri. We should still support
auth_uri for the time beaing.
Change-Id: I132fa8ebf91e932cd7fbc610dccd332348d52d49
Closes-Bug: #1764598