message: [wallet] Close bdb when flushing wallet.
  bdb would not be closed when closing the wallet in wallet-tool. Fix this
  by calling wallet->flush with true.
diff: @@ -17,7 +17,7 @@ namespace WalletTool {
  static void WalletToolReleaseWallet(CWallet* wallet)
  {
  wallet->WalletLogPrintf("Releasing wallet\n");
  - wallet->Flush();
  + wallet->Flush(true);
  delete wallet;
  }
  @@ -112,7 +112,7 @@ bool ExecuteWalletToolFunc(const std::string& command, const std::string& name)
  std::shared_ptr<CWallet> wallet_instance = CreateWallet(name, path);
  if (wallet_instance) {
  WalletShowInfo(wallet_instance.get());
  - wallet_instance->Flush();
  + wallet_instance->Flush(true);
  }
  } else if (command == "info") {
  if (!fs::exists(path)) {
  @@ -127,7 +127,7 @@ bool ExecuteWalletToolFunc(const std::string& command, const std::string& name)
  std::shared_ptr<CWallet> wallet_instance = LoadWallet(name, path);
  if (!wallet_instance) return false;
  WalletShowInfo(wallet_instance.get());
  - wallet_instance->Flush();
  + wallet_instance->Flush(true);
  } else {
  fprintf(stderr, "Invalid command: %s\n", command.c_str());
  return false;
  