Calling link::lo() may cause runtime error

  Try<set<string>> links = net::links();
  if (links.isError()) {
    return Error("Failed to get all the links: " + links.error());
  }
  foreach (const string& link, links.get()) {
    Result<bool> test = link::internal::test(link, IFF_LOOPBACK);
    if (test.isError()) {
      return Error("Failed to check the flag on link: " + link);
    } else if (test.get()) {
      return link;
    }
}

else if (test.isSome()) {
        if (test.get()) {
            return link;
        }
    }