port r16116 from 1.1: fix memleak

tests/main/get_children_tasks.c

@@ -72,6 +72,8 @@ int main(int argc, char **argv)
 
 	starpu_tag_notify_from_apps(0);
 
+	starpu_data_unregister(h);
+
 	starpu_shutdown();
 
 	STARPU_RETURN(ret?0:1);