ipvs: use list_del_init instead of list_del/INIT_LIST_HEAD

Using list_del_init() instead of list_del() + INIT_LIST_HEAD().

spatch with a semantic match is used to found this problem.
(http://coccinelle.lip6.fr/)

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Acked-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/ipvs/ip_vs_ctl.c

@@ -539,8 +539,7 @@ static int ip_vs_rs_unhash(struct ip_vs_dest *dest)
 	 * Remove it from the rs_table table.
 	 */
 	if (!list_empty(&dest->d_list)) {
-		list_del(&dest->d_list);
-		INIT_LIST_HEAD(&dest->d_list);
+		list_del_init(&dest->d_list);
 	}
 
 	return 1;