Add xenial param to prx and sl nodes

Change-Id: I71fc35b027496844cb509845d07ab5cc4a4567fb
diff --git a/classes/cluster/virtual-mcp-ocata-dvr/infra/config.yml b/classes/cluster/virtual-mcp-ocata-dvr/infra/config.yml
index 8eb05b8..0d85bae 100644
--- a/classes/cluster/virtual-mcp-ocata-dvr/infra/config.yml
+++ b/classes/cluster/virtual-mcp-ocata-dvr/infra/config.yml
@@ -85,6 +85,11 @@
           params:
             tenant_address: 10.1.0.110
             external_address: 10.16.0.110
+        openstack_proxy_node01:
+          classes:
+          - cluster.virtual-mcp-ocata-dvr.openstack.proxy
+          params:
+            linux_system_codename: xenial
         stacklight_server_node01:
           classes:
           - system.influxdb.server.single