Update keystone version info to include v3

[Henry Nash]

With the v3 api supported, we need to ensure keystone will return v3 as a listed version for a GET / url

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/23642

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/23642
Committed: http://github.com/openstack/keystone/commit/2dd6481a2005df7de0fed1fd630b8d2fbe38b775
Submitter: Jenkins
Branch: master

commit 2dd6481a2005df7de0fed1fd630b8d2fbe38b775
Author: Henry Nash <email address hidden>
Date: Wed Mar 6 01:54:27 2013 +0000

    Make Keystone return v3 as part of the version api

    The keystone "get version" api currently fails to list v3
    as a supported api. It should now do this, along with v2 (which is,
    of course, still supported)

    Fixes Bug #1148186

    Change-Id: Ie88bf941123702d2f7e2ecf6cecb1fa937ca1e52