src/common/utils.c: fix simgrid implementation of function starpu_usleep()

src/common/utils.c

@@ -552,7 +552,7 @@ void starpu_sleep(float nb_sec)
 void starpu_usleep(float nb_micro_sec)
 {
 #ifdef STARPU_SIMGRID
-	MSG_process_sleep(nb_sec / 1000000);
+	MSG_process_sleep(nb_micro_sec / 1000000);
 #elif defined(STARPU_HAVE_WINDOWS)
 	Sleep(nb_micro_sec / 1000);
 #elif HAVE_UNISTD_H