fixes #7813 - adds arguments to activation-key functions, BZ 1110475

This p-r is dependent upon https://github.com/Katello/hammer-cli-katello/pull/237
Looking at [host_collections#add_systems](https://github.com/Katello/katello/blob/master/app/controllers/katello/api/v2/host_collections_controller.rb#L94), this should probably be `PUT`.