MD: raid1 s/sysfs_notify_dirent/sysfs_notify_dirent_safe

If device-mapper creates a RAID1 array that includes devices to
be rebuilt, it will deref a NULL pointer when finished because
sysfs is not used by device-mapper instantiated RAID devices.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>

drivers/md/raid1.c

@@ -1031,7 +1031,7 @@ static int raid1_spare_active(mddev_t *mddev)
 		    && !test_bit(Faulty, &rdev->flags)
 		    && !test_and_set_bit(In_sync, &rdev->flags)) {
 			count++;
-			sysfs_notify_dirent(rdev->sysfs_state);
+			sysfs_notify_dirent_safe(rdev->sysfs_state);
 		}
 	}
 	spin_lock_irqsave(&conf->device_lock, flags);