[PATCH] md: remove nuisance message at shutdown

At shutdown, we switch all arrays to read-only, which creates a message for
every instantiated array, even those which aren't actually active.

So remove the message for non-active arrays.

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