DCACHE_UNHASHED in order to have a working /proc/$pid/fd/XXX.  Nothing in
proc prevents the fd link from being used if its dentry is not in the
hash.

Also, it does not get put into the dcache hash if DCACHE_UNHASHED is
clear; that depends on the filesystem calling d_add or d_rehash.

So delete the misleading comments and needless code.
Acked-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Davide Libenzi <davidel@xmailserver.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>