btrfs: fix nossd and ssd_spread mount option regression

The commit

07802534 btrfs: Cleanup the btrfs_parse_options for remount.

broke ssd options quite badly; it stopped making ssd_spread
imply ssd, and it made "nossd" unsettable.

Put things back at least as well as they were before
(though ssd mount option handling is still pretty odd:
# mount -o "nossd,ssd_spread" works?)
Reported-by: Roman Mamedov <rm@romanrm.net>
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Chris Mason <clm@fb.com>

fs/btrfs/super.c

@@ -522,9 +522,10 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
 		case Opt_ssd_spread:
 			btrfs_set_and_info(root, SSD_SPREAD,
 					   "use spread ssd allocation scheme");
+			btrfs_set_opt(info->mount_opt, SSD);
 			break;
 		case Opt_nossd:
-			btrfs_clear_and_info(root, NOSSD,
+			btrfs_set_and_info(root, NOSSD,
 					     "not using ssd allocation scheme");
 			btrfs_clear_opt(info->mount_opt, SSD);
 			break;