Make UpdateDeployment depend on NetworkDeployment

Make UpdateDeployment depend on NetworkDeployment

Prior to https://review.openstack.org/#/c/271450/ os-net-config was
applied via os-refresh-config directly, which meant that even though
UpdateDeployment and NetworkDeployment can be created concurrently,
we'd always do the os-net-config step first.

However now that we apply both steps via scripts (which are both handled
via the same heat-config hook) we should add an explicit dependency to
ensure the network is always fully configured before attempting to run
any update.  This should avoid the risk of e.g running an update on
initial deployment before the network connectivity to access yum repos
is in place.

Change-Id: Idff7a95afe7b49b6384b1d0c78e76522fb1f8eb7
Related-Bug: #1666227
(cherry picked from commit 626b820b57498ff5002c5530962e6e4fd5644b51)