Fix docker host at OpenContrail 4.0

PROD-20572

Change-Id: Ibf97906cf6d0113bd2e558c2b82a294f1ecf0179
diff --git a/opencontrail/control/control4_0.yml b/opencontrail/control/control4_0.yml
index 02ab75e..10c72ee 100644
--- a/opencontrail/control/control4_0.yml
+++ b/opencontrail/control/control4_0.yml
@@ -1,4 +1,5 @@
 classes:
+- service.docker.host
 - service.keepalived.cluster.single
 - service.opencontrail.control.control
 - system.haproxy.proxy.listen.opencontrail.control