Updated openstack/openstack
Project: openstack-infra/devstack-gate  ce1c40bca4b95ddb2d0e5cf00d59745bf2e273a3

Enable overriding of Ceilometer storage backend

That is needed to have gate jobs running on different backends.

Change-Id: Ib06f91d05ca3d8eb703b55dbac309fa5d0df7d49