Fix network configuration in contrail labs

Fixed by appending 50-cloud-init.cfg to /etc/network/interfaces, this avoids
bug in salt network module.

Change-Id: I5848025982b570d451db07d32f9fbe098a7a9fe6
diff --git a/classes/cluster/virtual-mcp11-contrail-nfv/openstack/compute.yml b/classes/cluster/virtual-mcp11-contrail-nfv/openstack/compute.yml
index 9a7b4a4..51217c4 100755
--- a/classes/cluster/virtual-mcp11-contrail-nfv/openstack/compute.yml
+++ b/classes/cluster/virtual-mcp11-contrail-nfv/openstack/compute.yml
@@ -31,6 +31,9 @@
     linux_system_codename: xenial
   linux:
     network:
+      concat_iface_files:
+      - src: '/etc/network/interfaces.d/50-cloud-init.cfg'
+        dst: '/etc/network/interfaces'
       interface:
         ens4:
           enabled: true
diff --git a/classes/cluster/virtual-mcp11-contrail/openstack/compute.yml b/classes/cluster/virtual-mcp11-contrail/openstack/compute.yml
index b1bd93c..967d151 100755
--- a/classes/cluster/virtual-mcp11-contrail/openstack/compute.yml
+++ b/classes/cluster/virtual-mcp11-contrail/openstack/compute.yml
@@ -26,6 +26,9 @@
     linux_system_codename: xenial
   linux:
     network:
+      concat_iface_files:
+      - src: '/etc/network/interfaces.d/50-cloud-init.cfg'
+        dst: '/etc/network/interfaces'
       interface:
         ens4:
           enabled: true