Do rabbit health check on worker 0 only

contrail-api workers > 0 are producers only, this patch disables
consumer health checks on workers with id > 0.

This silences log message:
Error in rabbitmq heartbeat greenlet: Too many heartbeats missed

Change-Id: I8d3a29b5c80c770c9b2bc924fd6d8d725fc9725b
Closes-Bug: #1756968

src/config/api-server/vnc_cfg_api_server/vnc_db.py

@@ -805,10 +805,14 @@ def db_client_init():
                 db_prefix=db_prefix, credential=db_credential)
             self._zk_db = self._object_db
 
+        health_check_interval = api_svr_mgr.get_rabbit_health_check_interval()
+        if api_svr_mgr.get_worker_id() > 0:
+            health_check_interval = 0.0
+
         self._msgbus = VncServerKombuClient(self, rabbit_servers,
             rabbit_port, rabbit_user, rabbit_password,
             rabbit_vhost, rabbit_ha_mode,
-            api_svr_mgr.get_rabbit_health_check_interval(),
+            health_check_interval,
             **kwargs)
     # end __init__