Currently "openstack" command on bridge doesn't work, because we need
cinder client pinned to an older version for RAX support. The
upstream container uses the latest versions of everything and it fails
to parse the "volume_api_version: 2" pin for RAX in the config file.
In general, the version of openstackclient we can probably most likely
rely on to work is the one from the launch-node virtualenv. It also
means we just have one place to manage a broadly-compatible version,
instead of trying to manage versions in separate containers, etc.
This converts the /usr/local/bin/openstack command from calling into
the container, to calling into the launch venv.
Change-Id: I604d5c17268a8219d51d432ba21feeb2e752a693
9e2d9f6aef