Remove obsolete workaround from dirserv_thinks_router_is_hs_dir()

There is this comment and code in dirserv_thinks_router_is_hs_dir() that can safely be removed now that tor-0.2.x is deprecated, right?

  /* XXX We shouldn't need to check dir_port, but we do because of
   * bug 1693. In the future, once relays set wants_to_be_hs_dir
   * correctly, we can revert to only checking dir_port if router's
   * version is too old. */
  /* XXX Unfortunately, we need to keep checking dir_port until all
   * *clients* suffering from bug 2722 are obsolete.  The first version
   * to fix the bug was 0.2.2.25-alpha. */
  return (router->wants_to_be_hs_dir && router->dir_port &&
          uptime >= get_options()->MinUptimeHidServDirectoryV2 &&
          router_is_active(router, node, now));