IPv6 management disabled by default

On systems where config_file_v6 is not set leaving ipv6 enabled leads to errors like:
Must pass emitter_target to Iptables::Concat_emitter[v6] at /tmp/vagrant-puppet/modules-0/iptables/manifests/concat_emitter.pp:7 on node centos63-64.example42.com
or
Error: Cannot alias File[/var/lib/puppet/concat/] to ["/var/lib/puppet/concat"] at /tmp/vagrant-puppet/modules-0/concat/manifests/init.pp:143; resource ["File", "/var/lib/puppet/concat"] already declared at /tmp/vagrant-puppet/modules-0/concat/manifests/setup.pp:54

An alternative solution could be to manage the value of enable_v6 according to the OS but having a different value according to the OS might be confusing.