It is a variation of existing fix_auth_url_version() call which
returns as a second value a boolean flag indicating whether the
auth_url was fixed to point to /v3 endpoint. So we could display a
more clear message to deployers from Horizon, based on the value of
this flag. The legacy fix_auth_url_version() call is to be phased out
as soon as Horizon cease to depend on it. Also provide a release note
about removing the old function.
Change-Id: I6c6a35b1c460e22dadf39634fce1bdfa257b8c63
Depends-On: I3a04d838a707465c8c6e81e0e6e2fcf918b7b059