proxy nodes fixes

Change-Id: I51b1f9812bae255421d1df1d63fb7ae7c601055d
diff --git a/classes/cluster/virtual-mcp11-contrail-nfv/infra/config.yml b/classes/cluster/virtual-mcp11-contrail-nfv/infra/config.yml
index b5f75de..a000956 100755
--- a/classes/cluster/virtual-mcp11-contrail-nfv/infra/config.yml
+++ b/classes/cluster/virtual-mcp11-contrail-nfv/infra/config.yml
@@ -186,4 +186,6 @@
             compute_vrouter_dpdk_pci: "'0000:00:04.0'"
         openstack_proxy_node01:
           classes:
-          - cluster.virtual-mcp11-contrail-nfv.openstack.proxy
\ No newline at end of file
+          - cluster.virtual-mcp11-contrail-nfv.openstack.proxy
+          params:
+            linux_system_codename: xenial
\ No newline at end of file