Run packstack pep8 and unit tests

Change-Id: Ifef61a7a29884ff669c321bab1ae8f284734dc3e
Reviewed-on: https://review.openstack.org/19692
Approved: James E. Blair <corvus@inaugust.com>
Reviewed-by: James E. Blair <corvus@inaugust.com>
Tested-by: Jenkins
Add zuul layout validation gate job.

Non-voting for now to make sure it works.

Change-Id: Iac29eba2320c8a972a03df81d10feb0183d98fd7
Reviewed-on: https://review.openstack.org/19719
Reviewed-by: Jeremy Stanley <fungi@yuggoth.org>
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Approved: James E. Blair <corvus@inaugust.com>
Reviewed-by: James E. Blair <corvus@inaugust.com>
Tested-by: Jenkins