[PATCH] knfsd: Restore functionality to read from file in /proc/fs/nfsd/

Most files in the nfsd filesystems are transaction files.  You write a
request, and read a response.

For some (e.g.  'threads') it makes sense to just be able to read and get the
current value.

This functionality did exist but was broken recently when someone modified
nfsctl.c without going through the maintainer.  This patch fixes the
regression.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>