Updated openstack/openstack
Project: openstack/python-keystoneclient  81e48d44ff79d58ec6b983f475ff008c9f7f3b0e

Document session usage first

Since we'd prefer developers to use the session method when
constructing the Client instance, document it first.

Change-Id: I8998a9962fd541bafae32b3443d7d4767da74257