center save shm on each node, no bind to shm.

lichao

2021-05-21 b2484c8bd77a9d21bcf1827f554444535196953d

 src/exported_symbols

@@ -5,6 +5,7 @@
   BHUnregister;
   BHRegisterTopics;
   BHQueryTopicAddress;
   BHQueryProcs;
   BHSubscribeTopics;
   BHStartWorker;
   BHHeartbeatEasy;