While replacing dst_pmtu in ip6_output I found this little gem.  In
ip6_forward we're not reloading the dst pointer after calling
xfrm6_route_forward.  So all subsequent dereferences of dst will
refer to its pre-IPsec value.

The solution is of course to refresh its value.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>