Ensure that superclasses' __init__ are called (#211)

mopidy/audio/mixers/fake.py

@@ -21,9 +21,6 @@ class FakeMixer(gst.Element, gst.ImplementsInterface, gst.interfaces.Mixer):
     track_flags = gobject.property(type=int, default=(
         gst.interfaces.MIXER_TRACK_MASTER | gst.interfaces.MIXER_TRACK_OUTPUT))
 
-    def __init__(self):
-        gst.Element.__init__(self)
-
     def list_tracks(self):
         track = utils.create_track(
             self.track_label,

mopidy/audio/mixers/nad.py

@@ -30,10 +30,8 @@ class NadMixer(gst.Element, gst.ImplementsInterface, gst.interfaces.Mixer):
     speakers_a = gobject.property(type=str)
     speakers_b = gobject.property(type=str)
 
-    def __init__(self):
-        gst.Element.__init__(self)
-        self._volume_cache = 0
-        self._nad_talker = None
+    _volume_cache = 0
+    _nad_talker = None
 
     def list_tracks(self):
         track = utils.create_track(

mopidy/backends/spotify/library.py

@@ -13,6 +13,7 @@ logger = logging.getLogger('mopidy.backends.spotify.library')
 class SpotifyTrack(Track):
     """Proxy object for unloaded Spotify tracks."""
     def __init__(self, uri):
+        super(SpotifyTrack, self).__init__()
         self._spotify_track = Link.from_string(uri).as_track()
         self._unloaded_track = Track(uri=uri, name=u'[loading...]')
         self._track = None