One should be able to set path_mtu value for neutron

Customer-Found
Change-Id: Ie100e957aeeba3a8e1747513b0793aeee5b7cd76
diff --git a/tests/pillar/control_cluster.sls b/tests/pillar/control_cluster.sls
index 763b549..bebff8c 100644
--- a/tests/pillar/control_cluster.sls
+++ b/tests/pillar/control_cluster.sls
@@ -2,6 +2,7 @@
   server:
     enabled: true
     fwaas: false
+    path_mtu: 1500
     dns_domain: novalocal
     tunnel_type: vxlan
     version: liberty