remove unnecessary variable

src/drivers/driver_common/driver_common.c

@@ -341,7 +341,6 @@ struct starpu_task *_starpu_get_worker_task(struct _starpu_worker *worker, int w
 {
 	STARPU_PTHREAD_MUTEX_LOCK_SCHED(&worker->sched_mutex);
 	struct starpu_task *task;
-	unsigned needed = 1;
 	unsigned executing STARPU_ATTRIBUTE_UNUSED = 0;
 
 	_starpu_worker_set_status_scheduling(workerid);