Remove unused $general_base_source/$::base_source

This also fixes an strict_variables error:
Undefined variable "::base_source"; Undefined variable "base_source" at .../modules/iptables/manifests/params.pp:149
Merge pull request #62 from sathieu/for_master

Remove unused $general_base_source/$::base_source
Merge branch 'master' of https://github.com/example42/puppet-iptables