Gemfile: Remove json, json_pure dependency for Ruby >= 2
Gemfile: Remove json, json_pure dependency for Ruby >= 2

We only need to pin json it down to < 2 on Ruby 1.9

Icinga/puppet-icinga2-rewrite,Icinga/puppet-icinga2-rewrite,Icinga/puppet-icinga2-rewrite,lazyfrosch/puppet-icinga2,lazyfrosch/puppet-icinga2,Icinga/puppet-icinga2,lazyfrosch/puppet-icinga2,Icinga/puppet-icinga2