ipv4: don't remove /proc/net/rt_acct

/proc/net/rt_acct is not created if NET_CLS_ROUTE=n.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index e446496..d62b05d 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -586,7 +586,9 @@
 {
 	remove_proc_entry("rt_cache", net->proc_net_stat);
 	remove_proc_entry("rt_cache", net->proc_net);
+#ifdef CONFIG_NET_CLS_ROUTE
 	remove_proc_entry("rt_acct", net->proc_net);
+#endif
 }
 
 static struct pernet_operations ip_rt_proc_ops __net_initdata =  {