acceptance: bump to Liberty release
acceptance: bump to Liberty release

Upgrade acceptance manifest from Kilo (stable) to Liberty (dev)
on Centos7.

Change-Id: I3bac96a607ec0067cdaab534d50ac302622f170f
Co-Authored-By: Lukas Bezdicka <cd3b060dff6ebb14bb9630beccc1dc4b65a0489a@redhat.com>

plumgrid/puppet-vswitch,openstack/puppet-vswitch,rdo-puppet-modules/puppet-vswitch,squarit/puppet-vswitch,openstack/puppet-vswitch