ipv6: Do not drop packet if skb->local_df is set to true

The old code will drop IPv6 packet if ipfragok is not set, since
ipfragok is obsoleted, will be instead by used skb->local_df, so this
check must be changed to skb->local_df.

This patch fix this problem and not drop packet if skb->local_df is
set to true.
Signed-off-by: NWei Yongjun <yjwei@cn.fujitsu.com>
Acked-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv6/ip6_output.c

@@ -269,7 +269,7 @@ int ip6_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl,
 	skb->mark = sk->sk_mark;
 
 	mtu = dst_mtu(dst);
-	if ((skb->len <= mtu) || ipfragok || skb_is_gso(skb)) {
+	if ((skb->len <= mtu) || skb->local_df || skb_is_gso(skb)) {
 		IP6_INC_STATS(ip6_dst_idev(skb->dst),
 			      IPSTATS_MIB_OUTREQUESTS);
 		return NF_HOOK(PF_INET6, NF_INET_LOCAL_OUT, skb, NULL, dst->dev,