sched: remove sched_exit()

remove sched_exit(): the elaborate dance of us trying to recover
timeslices given to child tasks never really worked.

CFS does not need it either.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/exit.c

@@ -182,7 +182,6 @@ repeat:
 		zap_leader = (leader->exit_signal == -1);
 	}
 
-	sched_exit(p);
 	write_unlock_irq(&tasklist_lock);
 	proc_flush_task(p);
 	release_thread(p);