While touching this code I noticed the error handling is bogus, so I
fixed it up.

I've removed the IS_ERR(proc_dentry) check, which will never trigger and
is clearly a typo: we must check proc_file instead.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>