acceptance: bump to Liberty

acceptance: bump to Liberty

RDO:
This patch changes the repositories used to install OpenStack Liberty on
RDO by using CBS repositories and RDO trunk.

Here is the RDO roadmap that is suggested if we want to run Liberty:
From now until GA:
http://trunk.rdoproject.org/centos7-liberty/current/
http://cbs.centos.org/repos/cloud7-openstack-liberty-testing/x86_64/os/
http://cbs.centos.org/repos/cloud7-openstack-common-testing/x86_64/os/

After GA:
http://mirror.centos.org/centos/7/cloud/x86_64/openstack-liberty

Note about EPEL: deps from EPEL are rebuilt in CBS, so EPEL could be
disabled in the future.

UCA:
Since our recent discussion about Ubuntu packaging, we decided to bump
Ubuntu packaging to trusty-proposed/liberty so we can install Liberty in
a better shape than current situation (Staging repo). This patch
installs UCA liberty repository.

Change-Id: Idd0beeec65b15798a015fa1c71486c75795d14ee