- Don't d_delete() files when removing a directory - they must still be 
  hashed when dput() reaps them, and it will __d_drop() them anyway.

- Don't d_invalidate() the directory on removal. 

- do simple_rmdir() after d_delete() on directory. 

- Remove extra dput(), which was causing refcount to go negative, causing 
  an oops when someone tried to create the directory again.

- Make sure we don't d_delete() or do extra dput() on file when updating, 
  either.