netfilter: nf_defrag_ipv4: Drop redundant ip_send_check()

Since commit 0848f642 ("inet: frags: fix defragmented packet's IP
header for af_packet"), ip_send_check() would be called twice for
defragmentation that occurs from netfilter ipv4 defrag hooks. Remove the
extra call.
Signed-off-by: Joe Stringer <joe@ovn.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/ipv4/netfilter/nf_defrag_ipv4.c

@@ -31,10 +31,8 @@ static int nf_ct_ipv4_gather_frags(struct net *net, struct sk_buff *skb,
 	err = ip_defrag(net, skb, user);
 	local_bh_enable();
 
-	if (!err) {
-		ip_send_check(ip_hdr(skb));
+	if (!err)
 		skb->ignore_df = 1;
-	}
 
 	return err;
 }