Do not give MpdDispatcher an MpdSession object yet, as it is not needed to get current tests passing

mopidy/frontends/mpd/dispatcher.py

@@ -24,9 +24,7 @@ class MpdDispatcher(object):
 
     # XXX Consider merging MpdDispatcher into MpdSession
 
-    def __init__(self, session):
-        self.session = session
-
+    def __init__(self):
         backend_refs = ActorRegistry.get_by_class(Backend)
         assert len(backend_refs) == 1, 'Expected exactly one running backend.'
         self.backend = backend_refs[0].proxy()

mopidy/frontends/mpd/session.py

@@ -23,7 +23,7 @@ class MpdSession(asynchat.async_chat):
         self.input_buffer = []
         self.authenticated = False
         self.set_terminator(LINE_TERMINATOR.encode(ENCODING))
-        self.dispatcher = MpdDispatcher(self)
+        self.dispatcher = MpdDispatcher()
 
     def start(self):
         """Start a new client session."""