Snapshot: Make sure a compatible track is selected before changing the play_mode

This is a fix for the snapshot class.  I have seen a problem where the play_mode is changed as per the saved snapshot, but the track that was previously playing has not been restored.  So if you were playing a stream after a snapshot and then try and restore Sonos will give you an error that you are trying to change the play_mode to one that is not supported.

Just switching the order solves this.

Please can this be flagged for 0.10