net: change proto destroy method to return void

Change struct proto destroy function pointer to return void.  Noticed
by Al Viro.

Signed-off-by: Brian Haley <brian.haley@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/udp_impl.h b/net/ipv4/udp_impl.h
index 7288bf7..2e9bad2 100644
--- a/net/ipv4/udp_impl.h
+++ b/net/ipv4/udp_impl.h
@@ -26,7 +26,7 @@
 extern int	udp_sendpage(struct sock *sk, struct page *page, int offset,
 			     size_t size, int flags);
 extern int	udp_queue_rcv_skb(struct sock * sk, struct sk_buff *skb);
-extern int	udp_destroy_sock(struct sock *sk);
+extern void	udp_destroy_sock(struct sock *sk);
 
 #ifdef CONFIG_PROC_FS
 extern int	udp4_seq_show(struct seq_file *seq, void *v);