Add opencontrail_version parameter to horizon/server/plugin/contrail and default it to 3.2

Change-Id: Id499bc81ebe944198ce4d89d08c6ffb6aa47d44e
diff --git a/horizon/server/plugin/contrail.yml b/horizon/server/plugin/contrail.yml
index 03da87e..9166bce 100644
--- a/horizon/server/plugin/contrail.yml
+++ b/horizon/server/plugin/contrail.yml
@@ -1,4 +1,6 @@
 parameters:
+  _param:
+    opencontrail_version: 3.2
   horizon:
     server:
       plugin:
@@ -6,8 +8,9 @@
           source:
             engine: pkg
             name: openstack-dashboard-contrail-panels
+          opencontrail_version: ${_param:opencontrail_version}
         horizon_overrides:
           overrides:
           - contrail_openstack_dashboard
       openstack_neutron_network:
-        enable_fip_topology_check: False
\ No newline at end of file
+        enable_fip_topology_check: False