Updated openstack/openstack
Project: openstack/keystone  10831618368f97a4521aeff8edf3efa5a8a8a663

Use true() rather than variable/singleton

SqlAlchemy provides a true() factory so we don't have to work around
PEP8 issues with comparing singletons.

Change-Id: Icdff30d85beb068d10b987aea0e5a6e71098316a