Updated openstack/openstack
Project: openstack/keystone  24f101737c9a007cbcb9dd7fde00f3a422f313a1

Update architecture documentation

The architecture docs are very dated, and have several references
to tenants, PAM backends, and controllers that don't exist.

Change-Id: I85de743006e7df4fcf8ddbc3afc1a4bcd69583e6