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: David S. Miller <davem@davemloft.net>
diff --git a/net/econet/af_econet.c b/net/econet/af_econet.c
index 7c9bb13..d35127b 100644
--- a/net/econet/af_econet.c
+++ b/net/econet/af_econet.c
@@ -573,9 +573,7 @@
 
 	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 */