Fixed a bug where the storage service might crash (vesoft-inc#583)

  When the storage service deamon is started, the nebula::meta::MetaClient
  will use the MetaServerBasedPartManager object(MetaClient::registerListener),
  but the MetaServerBasedPartManager object will be released before
  nebula::meta::MetaClient(through KVStore object), so we need to manually
  release nebula::meta::MetaClient here before release KVStore object.

src/daemons/StorageDaemon.cpp

@@ -154,21 +154,20 @@ int main(int argc, char *argv[]) {
  auto ioThreadPool = std::make_shared<folly::IOThreadPoolExecutor>(FLAGS_num_io_threads);
 
  // Meta client
- auto metaClient = std::make_unique<nebula::meta::MetaClient>(ioThreadPool,
- std::move(metaAddrsRet.value()),
- true);
+ auto metaClient = new nebula::meta::MetaClient(
+ ioThreadPool, std::move(metaAddrsRet.value()), true);
  metaClient->init();
 
  LOG(INFO) << "Init schema manager";
  auto schemaMan = nebula::meta::SchemaManager::create();
- schemaMan->init(metaClient.get());
+ schemaMan->init(metaClient);
 
  LOG(INFO) << "Init kvstore";
  std::unique_ptr<KVStore> kvstore = getStoreInstance(localhost,
  std::move(paths),
  ioThreadPool,
  workers,
- metaClient.get(),
+ metaClient,
  schemaMan.get());
 
  LOG(INFO) << "Starting Storage HTTP Service";
@@ -200,10 +199,12 @@ int main(int argc, char *argv[]) {
  gServer->setIOThreadPool(ioThreadPool);
  gServer->serve(); // Will wait until the server shuts down
  } catch (const std::exception& e) {
+ delete metaClient;
  LOG(ERROR) << "Start thrift server failed, error:" << e.what();
  return EXIT_FAILURE;
  }
 
+ delete metaClient;
  LOG(INFO) << "The storage Daemon stopped";
 }