With keystone's move to eliminating pki, pkiz, and uuid tokens the
revocation list is no longer generated. Keystonemiddleware no longer
needs to attempt to retrieve it and reference it.
Change-Id: Ief3bf1941e62f9136dbed11877bca81c4102041b
closes-bug: #1361743
partial-bug: #1649735
partial-bug: #1736985