act: fix the logic of parsing actions

It is proved that actions are not always put from 0,
they could be discontinuous.

http://lists.infradead.org/pipermail/libnl/2014-April/001374.html

Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Thomas Haller <thaller@redhat.com>

lib/route/act.c

@@ -396,9 +396,12 @@ int rtnl_act_parse(struct rtnl_act **head, struct nlattr *tb)
 	if (err < 0)
 		return err;
 
-	for (i = 0; i < TCA_ACT_MAX_PRIO && nla[i]; i++) {
+	for (i = 0; i < TCA_ACT_MAX_PRIO; i++) {
 		struct rtnl_tc *tc;
 
+		if (nla[i] == NULL)
+			continue;
+
 		act = rtnl_act_alloc();
 		if (!act) {
 			err = -NLE_NOMEM;