fix leak in btrfs_drop_snapshot

Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 997cc57..c9201ec 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -167,7 +167,7 @@
 		root->node->count++;
 		ret = btrfs_drop_snapshot(root, snap);
 		BUG_ON(ret);
-		tree_block_release(root, snap);
+		// tree_block_release(root, snap);
 	}
         write_ctree_super(root, s);
 	btrfs_finish_extent_commit(root);