Updated openstack/openstack
Project: openstack/keystone  9d4e22b4976efea7326900ca9f44db146b0be269

Adds hint about filter placement to extension docs

Since a filter cannot be the last entry in a pipeline it makes sense to
call that out in the extension documentation.

Change-Id: Idf73bdb6d6d237cbf9d108f67eeb8020caeaa364
Related-Bug: #1363932