netfilter: ipset: hash:*net*: nomatch flag not excluded on set resize

If a resize is triggered the nomatch flag is not excluded at hashing,
which leads to the element missed at lookup in the resized set.

Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>