ipv4: fix for ip_options_rcv_srr() daddr update.

When opt->srr_is_hit is set skb_rtable(skb) has been updated for
'nexthop' and iph->daddr should always equals to skb_rtable->rt_dst
holds, We need update iph->daddr either.

Signed-off-by: Li Wei <lw@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>