Don't change mtime/ctime/atime to local time on read/write.  Rather invalidate
file attributes, so next stat() will force a GETATTR call.  Bug reported by
Ben Grimm.
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>