- Simplified the flist-spanning gnum logic in match_gnums().

- Simplified the flist-spanning gnum logic in match_gnums().
- Don't use hlink_flist in hard_link_check().
- Made the prev_name logic in hard_link_check() better.
- Added an "ndx" arg to the finish_hard_link() call.  Also, set the
  prev value of any prior entries to the first finished item (which
  ensures that any item that follows a re-shuffled item (which was
  waiting for a transferred file to finish) can find the FIRST+DONE
  item.