Add /lib/modules as volume to openvswitch_db container

Change-Id: I1267e9d49f8190e4998d6a8164b1e68c613de2bc
Closes-bug: #1712780

ansible/roles/openvswitch/defaults/main.yml

@@ -19,6 +19,7 @@ openvswitch_services:
     volumes:
       - "{{ node_config_directory }}/openvswitch-db-server/:{{ container_config_directory }}/:ro"
       - "/etc/localtime:/etc/localtime:ro"
+      - "/lib/modules:/lib/modules:ro"
       - "/run:/run:shared"
       - "kolla_logs:/var/log/kolla/"
       - "openvswitch_db:/var/lib/openvswitch/"