doc: remove "pay-per-view" comment
doc: remove "pay-per-view" comment

Havn't heard of this plan for a few years, and I'm not sure if
somebody is still working on it.

CM4all/beng-proxy,CM4all/beng-proxy,CM4all/beng-proxy,CM4all/beng-proxy,CM4all/beng-proxy,CM4all/beng-proxy