cache_tree_free: Fix small memory leak

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

cache-tree.c

@@ -22,8 +22,10 @@ void cache_tree_free(struct cache_tree **it_p)
 	if (!it)
 		return;
 	for (i = 0; i < it->subtree_nr; i++)
-		if (it->down[i])
+		if (it->down[i]) {
 			cache_tree_free(&it->down[i]->cache_tree);
+			free(it->down[i]);
+		}
 	free(it->down);
 	free(it);
 	*it_p = NULL;