Also switch to PFS routing mode when doing a smoketest.

It's not usable because we need to provide valid metadata,
which includes correctly signed user IDs.

Instead of calling query_address_metadata and query_paths directly,
we should now call methods on PFSProxy. This allows us to tweak the
behaviour and provide valid metadata in tests more easily.

RaidenService is a Runnable, which implements __bool__ that checks
whether the greenlet is running, which is not what we want to test here.
Instead, we'd like to check against None, but since the service will
not be None here, remove the check completely.

… started yet