Add hacking and pbr to openstack-infra channel.

Change-Id: I076ef38a0cb6be82b6ba8c94e5605d09459a6517
Reviewed-on: https://review.openstack.org/27426
Reviewed-by: Anita Kuno <anita.kuno@enovance.com>
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