"disk" is always NULL when we goto out.  There was a check for this
before, but it was removed in 69e02c59 "block: Don't check events
while open is in progress".
Signed-off-by: NDan Carpenter <error27@gmail.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@carl>