Enable HAProxy checks for contrail-api

https://github.com/Mirantis/mk-lab-salt-model/pull/184
diff --git a/haproxy/proxy/listen/opencontrail/control.yml b/haproxy/proxy/listen/opencontrail/control.yml
index 99087ef..c389682 100644
--- a/haproxy/proxy/listen/opencontrail/control.yml
+++ b/haproxy/proxy/listen/opencontrail/control.yml
@@ -5,7 +5,6 @@
         contrail_api:
           type: contrail-api
           service_name: contrail
-          check: false
           binds:
           - address: ${_param:cluster_vip_address}
             port: 8082