This is a little optimisation for AH4.  When I moved the tunnel code out,
I put the daddr copying code on the main path which is unnecessary since
daddr is only mutable if IP options are present.

This patch moves the saving and restoring of daddr under the check for
the existence of IP options.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@redhat.com>