- Turned readlink_stat() into a static function.

- Made readlink_stat() no longer honor keep_dirlinks.
- The make_file() function now checks keep_dirlinks late in the
  function so that it only transforms a symlink to a local dir
  into a directory if the receiver also has a directory by that
  name.  This makes the use of --delete with --keep-dirlinks
  work much better.