doc: sync usage with recent changes

The documentation was missing recent optional arguments such as
--version.

Change-Id: Iad111d2f5c14c54d1495f2ba837627e0ea42acb0
Reviewed-on: https://review.openstack.org/27172
Reviewed-by: Jesse Keating <jesse.keating@rackspace.com>
Reviewed-by: Khai Do <zaro0508@gmail.com>
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Approved: Jeremy Stanley <fungi@yuggoth.org>
Reviewed-by: Jeremy Stanley <fungi@yuggoth.org>
Tested-by: Jenkins