Merge tag 'md/3.18-fix' of git://neil.brown.name/md

Pull md bugfix from Neil Brown:
"One fix for md for 3.18.

This fixes a regression introduced in 3.13"

* tag 'md/3.18-fix' of git://neil.brown.name/md:
md: Always set RECOVERY_NEEDED when clearing RECOVERY_FROZEN

drivers/md/md.c

···
 		printk("md: %s still in use.\n",mdname(mddev));
 		if (did_freeze) {
 			clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
+			set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 			md_wakeup_thread(mddev->thread);
 		}
 		err = -EBUSY;
···
 		mddev->ro = 1;
 		set_disk_ro(mddev->gendisk, 1);
 		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
+		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+		md_wakeup_thread(mddev->thread);
 		sysfs_notify_dirent_safe(mddev->sysfs_state);
 		err = 0;
 	}
···
 		mutex_unlock(&mddev->open_mutex);
 		if (did_freeze) {
 			clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
+			set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 			md_wakeup_thread(mddev->thread);
 		}
 		return -EBUSY;