add support for building with grails

Change-Id: Ie5caf99bdbe6f6f5493511d2710ee04747fb0494
Reviewed-on: https://review.openstack.org/28125
Reviewed-by: Jeremy Stanley <fungi@yuggoth.org>
Approved: Clark Boylan <clark.boylan@gmail.com>
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Tested-by: Jenkins