Keep the default network=writeback setting, but allow it
to come from hiera overrides as well.
Conflicts:
manifests/profile/base/nova/compute_libvirt_shared.pp
Change-Id: I47aaf4be463684f5b67820b8ebb5db44ba960b44
Signed-off-by: Bogdan Dobrelya <bdobreli@redhat.com>
(cherry picked from commit f12a143f52)