Sharing the open sequence queue causes a deadlock when we try to take
both a lock sequence id and and open sequence id.

This fixes the regression reported by Dimitri Puzin and Jeff Garzik: See

	http://bugzilla.kernel.org/show_bug.cgi?id=9712

for details.
Reported-and-tested-by: NDimitri Puzin <bugs@psycast.de>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Tested-by: NJeff Garzik <jgarzik@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>