Enable multipathd health check

This patch enables health check execution for multipathd docker container.

Change-Id: If320fcd3ed2658dda9ce0dfb7f14c717ffdc03a1
Depends-On: If9476b2dd485f8399d10289989ba74a2c1f58626

docker/services/multipathd.yaml

@@ -71,6 +71,8 @@ outputs:
             net: host
             privileged: true
             restart: always
+            healthcheck:
+              test: /openstack/healthcheck
             volumes:
               list_concat:
                 - {get_attr: [ContainersCommon, volumes]}