Enable neutron to work in a multi node setup

On the controller node where devstack is being run should create
the neutron network. The compute node should not.

The the case that we want to run a multi-node neutron setup we need
to configure the following (in the case that a plugin does not
have any agents running on the compute node):
ENABLED_SERVICES=n-cpu,neutron

In addition to this the code did not enable decomposed plugins to
configure their nova configurations if necessary.

This patch ensure that the multi-node support works.

Change-Id: I8e80edd453a1106ca666d6c531b2433be631bce4
Closes-bug: #1613069
diff --git a/stack.sh b/stack.sh
index 823b63b..ce34cd5 100755
--- a/stack.sh
+++ b/stack.sh
@@ -1248,10 +1248,7 @@
     start_neutron
 fi
 # Once neutron agents are started setup initial network elements
-if is_service_enabled q-svc && [[ "$NEUTRON_CREATE_INITIAL_NETWORKS" == "True" ]]; then
-    echo_summary "Creating initial neutron network elements"
-    create_neutron_initial_network
-fi
+create_neutron_initial_network
 
 if is_service_enabled nova; then
     echo_summary "Starting Nova"