Run Neutron migrations after creating schema

Partial-Bug 1207402

This patch executes Neutron DB migrations (based on alembic)
before starting the Neutron services, similar to what happens
for most of other openstack projects managed by devstack.
This will ensure devstack always creates correctly version-stamped
Neutron databases.

Change-Id: Ia941c426a1563bcc4cb5eae64ea30c0bf7677220
diff --git a/stack.sh b/stack.sh
index 5ba60d2..01f948e 100755
--- a/stack.sh
+++ b/stack.sh
@@ -939,7 +939,10 @@
     echo_summary "Configuring Neutron"
 
     configure_neutron
-    init_neutron
+    # Run init_neutron only on the node hosting the neutron API server
+    if is_service_enabled $DATABASE_BACKENDS && is_service_enabled q-svc; then
+        init_neutron
+    fi
 fi
 
 # Some Neutron plugins require network controllers which are not