- Changed the dir_flist code on the sending side to derive its sorted

- Changed the dir_flist code on the sending side to derive its sorted
  data from the sorted parent flist.  This ensures that any entries
  marked with FLAG_DUPLICATE are in the same order in the dir_flist
  (where the flags get checked) as they are in the parent flist
  (where the flags get set).
- Made the flist_expand() function static.
- Added a growth count arg to flist_expand().
- Made make_file() set a pool variable instead of tweaking flist.
- Improved the error message when a dir-number is out of bounds.