proxy nodes fixes

Change-Id: I51b1f9812bae255421d1df1d63fb7ae7c601055d
diff --git a/classes/cluster/virtual-mcp11-contrail/infra/config.yml b/classes/cluster/virtual-mcp11-contrail/infra/config.yml
index d73aba5..28cc045 100755
--- a/classes/cluster/virtual-mcp11-contrail/infra/config.yml
+++ b/classes/cluster/virtual-mcp11-contrail/infra/config.yml
@@ -179,3 +179,5 @@
         openstack_proxy_node01:
           classes:
           - cluster.virtual-mcp11-contrail.openstack.proxy
+          params:
+            linux_system_codename: xenial
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