We weren't actually checking for SHARE_ACCESS_WRITE, with the result that the
owner could open a non-writeable file for write!

Continue to allow DENY_WRITE only with write access.

Thanks to Jim Rees for reporting the bug.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: NNeil Brown <neilb@suse.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>