Bind vRouter on control address by default

Change-Id: Ib49712de81f513c27442d591568d6a5573b983cc
diff --git a/opencontrail/compute/cluster.yml b/opencontrail/compute/cluster.yml
index 375e600..d10b361 100644
--- a/opencontrail/compute/cluster.yml
+++ b/opencontrail/compute/cluster.yml
@@ -20,6 +20,8 @@
       version: ${_param:opencontrail_version}
       disable_flow_collection: true
       enabled: True
+      bind:
+        address: ${_param:single_address}
       discovery:
         host: ${_param:opencontrail_control_address}
       interface: