Most OpenStack clients support a common set of SSL options, such
as os-cacert, os-cert, and os-key. This change uses
keystoneclient.session.register_cli_opts to add those to the
argument parser and passes the resulting values to the Keystone
client so they take effect.
Change-Id: I24c2c2fa5be51590cc2d8a9278563dd4f7ba091d