sched_policies: add a comment related to USE_OVERLOAD experimental code

src/sched_policies/work_stealing_policy.c

@@ -29,6 +29,9 @@
 #include <Ayudame.h>
 #endif
 
+/* Experimental (dead) code which needs to be tested, fixed... */
+/* #define USE_OVERLOAD */
+
 struct _starpu_work_stealing_data
 {
 	struct _starpu_fifo_taskq **queue_array;