[IPV6] ADDRCONF: Fix default source address selection without CONFIG_IPV6_PRIVACY

We need to update hiscore.rule even if we don't enable CONFIG_IPV6_PRIVACY,
because we have more less significant rule; longest match.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>