Update to Move libvirt options into a group

Nova has moved the the libvirt options into a group
in the config file, this patch aligns packstack templates
to this new configuration.
This patch needs this pull request to be approved first:
https://github.com/redhat-openstack/openstack-puppet-modules/pull/37

Conflicts:

	packstack/puppet/templates/nova_compute_libvirt.pp

Change-Id: I14027588dd10e8e13af356ec53a9958f49039fb1
Fixes: rhbz#1093925
(cherry picked from commit c76b33c1e399cecbbce7a87b9dfe6bcaa8929d47)