econet: Use sock_orphan() instead of open-coded (and buggy) variant.

It doesn't grab the sk_callback_lock, it doesn't NULL out
the sk->sk_sleep waitqueue pointer, etc.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/econet/af_econet.c

@@ -573,9 +573,7 @@ static int econet_release(struct socket *sock)
 
 	sk->sk_state_change(sk);	/* It is useless. Just for sanity. */
 
-	sock->sk = NULL;
-	sk->sk_socket = NULL;
-	sock_set_flag(sk, SOCK_DEAD);
+	sock_orphan(sk);
 
 	/* Purge queues */