center remove old shm on start.

lichao

2021-06-03 d89ff0ad812cdf178b911843bc3e8c04b2f00845

 src/defs.cpp

@@ -175,6 +175,8 @@

   auto pmeta = GetBHomeMeta();
   if (pmeta && pmeta->tag_ == kMetaInfoTag) {
      // remove old shm
      SharedMemory::Remove(BHomeShmName());
      ++pmeta->shm_id_; // inc shm id
      return true;      // already exist.
   } else {