Set mgmt interfaces to dhcp in contrail-labs

Closes-bug: #PROD-23882

Change-Id: I0d9faa34f92d4e771e28a7fe7e9ab1e33f3990ff
diff --git a/classes/cluster/os-ha-contrail-40/openstack/compute.yml b/classes/cluster/os-ha-contrail-40/openstack/compute.yml
index 4dc427e..734885f 100644
--- a/classes/cluster/os-ha-contrail-40/openstack/compute.yml
+++ b/classes/cluster/os-ha-contrail-40/openstack/compute.yml
@@ -36,6 +36,7 @@
       - src: '/etc/network/interfaces.d/50-cloud-init.cfg'
         dst: '/etc/network/interfaces'
       interface:
+        ens3: ${_param:linux_dhcp_interface}
         ens4:
           enabled: true
           ipflush_onchange: true