Update actor.py

[nolyn]

Statment next_uris == uri was not working as intented, causing mopidy to get stuck in endless loop.

[kingosticks]

Oh dear, what I had before was total garbage (need tests).

This PR doesn't do quite what I was trying to do. It's supposed to be more of a last ditch attempt which we only do if there are no more uris left to try. We've already tried (and failed) to use uri so if parse_stream_url returns it back to us it's not that interesting unless we've got nothing else to work with.

It's a big hack, the fact that the scan can fail but the uri is playable is the real issue here. But this PR is much better than an infinite loop, so thanks.