Update keystone configuration for Mitaka.
1) Change token type from UUID with Memcached to Fernet.
2) Complete migration to the Identity v3 API. As testing
progresses, some services may require additional
changes.
Note: Still contemplating use of clouds.yaml. Initial
investigation indicates insufficient positive
impact for the changes necessary to implement it.
Note: The keystone authentication library for services
(keystoneauth1) requires Memcached in Mitaka. A
future patch will move installation of Memcached
to the environment content.
Change-Id: Ifdf96c285f1b260822922661668bc30629328ade
Implements: bp installguide-mitaka
bd9b8b65d4