Because skb->dst is assigned in ip6_route_input(), it is really
bad to use it in hop-by-hop option handler(s).
Closes: Bug #8450 (Eric Sesterhenn <snakebyte@gmx.de>) Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>