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/include/net/sock.h b/include/net/sock.h
index dc42b44..0a80961 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -524,7 +524,7 @@
 	int			(*ioctl)(struct sock *sk, int cmd,
 					 unsigned long arg);
 	int			(*init)(struct sock *sk);
-	int			(*destroy)(struct sock *sk);
+	void			(*destroy)(struct sock *sk);
 	void			(*shutdown)(struct sock *sk, int how);
 	int			(*setsockopt)(struct sock *sk, int level, 
 					int optname, char __user *optval,