Make sure libvirt guests shut down before network
Make sure libvirt guests shut down before network

Make tripleo_nova_libvirt_guests service requiring network-online.target
so that network won't get off until instances are (gracefully) shutdown.

Change-Id: I9b426fad3722ae2f395624d86d704b60e9fa5e7a
Related: rhbz#2031124
Signed-off-by: Bogdan Dobrelya <a2228ae37d00d1cbd5a93e53f3e1e5aef21d5900@redhat.com>

openstack/tripleo-heat-templates,openstack/tripleo-heat-templates