Remove contrail_discovery from haproxy conf for OC 4.0

Contrail-Discovery service was removed from OpenContrail starting
from version 4.0. This way we need to remove related records from
haproxy configurations for deployments of OC 4.0

Change-Id: Ifa286892041648179b4e2fa7e13ffe8ba4cb4845
Related-Bug: PROD-23817
diff --git a/opencontrail/control/cluster4_0.yml b/opencontrail/control/cluster4_0.yml
index c97196f..ed28f71 100644
--- a/opencontrail/control/cluster4_0.yml
+++ b/opencontrail/control/cluster4_0.yml
@@ -2,7 +2,7 @@
 - service.haproxy.proxy.single
 - service.keepalived.cluster.single
 - service.opencontrail.control.cluster
-- system.haproxy.proxy.listen.opencontrail.control
+- system.haproxy.proxy.listen.opencontrail.control4_0
 - system.haproxy.proxy.listen.opencontrail.analytics
 parameters:
   _param: