IPVS: Minimise ip_vs_leave when CONFIG_SYSCTL is undefined

Much of ip_vs_leave() is unnecessary if CONFIG_SYSCTL is undefined.

I tried an approach of breaking the now #ifdef'ed portions out
into a separate function. However this appeared to grow the
compiled code on x86_64 by about 200 bytes in the case where
CONFIG_SYSCTL is defined. So I have gone with the simpler though
less elegant #ifdef'ed solution for now.
Signed-off-by: Simon Horman <horms@verge.net.au>

net/netfilter/ipvs/ip_vs_core.c

@@ -499,11 +499,13 @@ ip_vs_schedule(struct ip_vs_service *svc, struct sk_buff *skb,
 int ip_vs_leave(struct ip_vs_service *svc, struct sk_buff *skb,
 		struct ip_vs_proto_data *pd)
 {
-	struct net *net;
-	struct netns_ipvs *ipvs;
 	__be16 _ports[2], *pptr;
 	struct ip_vs_iphdr iph;
+#ifdef CONFIG_SYSCTL
+	struct net *net;
+	struct netns_ipvs *ipvs;
 	int unicast;
+#endif
 
 	ip_vs_fill_iphdr(svc->af, skb_network_header(skb), &iph);
 
@@ -512,6 +514,8 @@ int ip_vs_leave(struct ip_vs_service *svc, struct sk_buff *skb,
 		ip_vs_service_put(svc);
 		return NF_DROP;
 	}
+
+#ifdef CONFIG_SYSCTL
 	net = skb_net(skb);
 
 #ifdef CONFIG_IP_VS_IPV6
@@ -563,6 +567,7 @@ int ip_vs_leave(struct ip_vs_service *svc, struct sk_buff *skb,
 		ip_vs_conn_put(cp);
 		return ret;
 	}
+#endif
 
 	/*
 	 * When the virtual ftp service is presented, packets destined