netfilter: ipset: Use the stored first cidr value instead of '1'

The stored cidr values are tried one after anoter. The boolean
condition evaluated to '1' instead of the first stored cidr or
the default host cidr.

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