Savanna Horizon plugin added and small cleanup

* pyflakes job removed from all Savanna projects
* missed description added for all Savanna projects

Change-Id: I5348f6b102a81ccbc69c624554b22a7aea3d8ee0
Reviewed-on: https://review.openstack.org/29283
Reviewed-by: Jeremy Stanley <fungi@yuggoth.org>
Reviewed-by: James E. Blair <corvus@inaugust.com>
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Approved: James E. Blair <corvus@inaugust.com>
Tested-by: Jenkins