[IPV4]: Kill fib4_rules_clean().

As noted by Adrian Bunk this function is totally unused.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/ip_fib.h

@@ -254,7 +254,6 @@ extern struct fib_table *fib_hash_init(int id);
 extern int fib4_rules_dump(struct sk_buff *skb, struct netlink_callback *cb);
 
 extern void __init fib4_rules_init(void);
-extern void __exit fib4_rules_cleanup(void);
 
 #ifdef CONFIG_NET_CLS_ROUTE
 extern u32 fib_rules_tclass(struct fib_result *res);

net/ipv4/fib_rules.c

@@ -347,8 +347,3 @@ void __init fib4_rules_init(void)
 
 	fib_rules_register(&fib4_rules_ops);
 }
-
-void __exit fib4_rules_cleanup(void)
-{
-	fib_rules_unregister(&fib4_rules_ops);
-}