client: update the help of `create` command

This patch updates the help of the `create` command
to keep up with last changes.

Change-Id: I8a1f755d3586a232e3645afc2ebe6613814225cc
Signed-off-by: Francesco Romani <fromani@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/24150
Reviewed-by: Dan Kenigsberg <danken@redhat.com>