message: add code comment.
diff: @@ -1700,6 +1700,7 @@ void write_default_config(const bfs::path& cfg_file, const options_description &
  {
  if(!od->description().empty()) {
  out_cfg << "# " << od->description();
  + // disable uninitialized variable usage.
  // std::map<std::string, std::string>::iterator it;
  // out_cfg << " (" << it->second << ")";
  out_cfg << std::endl;
  