unused helper ZeitgeistRemoteDataSourceRegistryTest._register_data_source_python_api() is broken

[Markus Korn]

I'm talking about

 def _register_data_source_python_api(self, *args):
  mainloop = gobject.MainLoop()
  self.client.register_data_source(*args,
   reply_handler=lambda: mainloop.quit(),
   error_handler=lambda: fail("Error registering data-source"))
  mainloop.run()

* In error_handler it should be self.fail(...)
* register_data_source() has no reply_handler/error_handler arguments

On the other hand, this method isn't used anywhere

@Siegfried, I think you added this code recently, can you please fix it. Thanks so much ;)

[Siegfried Gevatter (rainct)]

Yeah, removed that. Thanks for spotting.