ipv6: cancel to setting local_df in ip6_xmit()

commit f88037(sctp: Drop ipfargok in sctp_xmit function)
has droped ipfragok and set local_df value properly.

So the change of commit 77e2f1(ipv6: Fix ip6_xmit to
send fragments if ipfragok is true) is not needed.
So the patch remove them.
Signed-off-by: NShan Wei <shanwei@cn.fujitsu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv6/ip6_output.c

@@ -231,10 +231,6 @@ int ip6_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl,
 	skb_reset_network_header(skb);
 	hdr = ipv6_hdr(skb);
 
-	/* Allow local fragmentation. */
-	if (ipfragok)
-		skb->local_df = 1;
-
 	/*
 	 *	Fill in the IPv6 header
 	 */