Description of problem: In the 10.8 API, there is not a method available to list the systems subscribed to a particular configuration channel. A method such as configchannel.listSubscribedSystems(session, channel) would be perfect to fill this void. Version-Release number of selected component (if applicable): Satellite 5.3.0
configchannel.listSubscribedSystems api introduced spacewalk.git: 1c3f3d5a7469c940b5c4f03fb2a9183d15d15fc3 a50fc26d15e50f47a7e8c01d5cfae2f253517216