util.pubsub: Handle absence of node data interface This is in preparation for fixing the behavior of 'persist_items', which was misunderstood at some point. In mod_pep it toggles between persistent storage and in-memory storage, while the correct behavior would be to toggle whether published items are stored at all or forgotten after being broadcast.

-- Unknown platform stub
module:set_global();

-- TODO Do things that make sense if we don't know about the platform