message: Make sure portForNewAccessKeys is written
diff: @@ -77,6 +77,7 @@ async function reservePortForNewAccessKeys(
  portProvider: PortProvider,
  serverConfig: json_config.JsonConfig<server_config.ServerConfigJson>): Promise<number> {
  serverConfig.data().portForNewAccessKeys = await portProvider.reserveNewPort();
  + serverConfig.write();
  return serverConfig.data().portForNewAccessKeys;
  }
  