Updated openstack/openstack
Project: openstack-infra/devstack-gate  89d15892582b85d67a56ade8d68aff1bdf633463

Cleanup grenade machinery in prep for Juno

Over the Juno cycle we made changes to how we process grenade config in
devstack gate. We did so in a backward compatible way for our old jobs.
Clean up the now no longer needed backward compat code to make new Juno
grenade testing simpler.

Change-Id: I08736a5a1d3d55fe20b95c740e69f4557add46fc