Fix roomlist since tokens on Python 3 (#4046)

Thanks @Half-Shot !!!

synapse/handlers/room_list.py

@@ -16,7 +16,7 @@
 import logging
 from collections import namedtuple
 
-from six import iteritems
+from six import PY3, iteritems
 from six.moves import range
 
 import msgpack
@@ -444,9 +444,16 @@ class RoomListNextBatch(namedtuple("RoomListNextBatch", (
 
     @classmethod
     def from_token(cls, token):
+        if PY3:
+            # The argument raw=False is only available on new versions of
+            # msgpack, and only really needed on Python 3. Gate it behind
+            # a PY3 check to avoid causing issues on Debian-packaged versions.
+            decoded = msgpack.loads(decode_base64(token), raw=False)
+        else:
+            decoded = msgpack.loads(decode_base64(token))
         return RoomListNextBatch(**{
             cls.REVERSE_KEY_DICT[key]: val
-            for key, val in msgpack.loads(decode_base64(token)).items()
+            for key, val in decoded.items()
         })
 
     def to_token(self):

synapse/python_dependencies.py

@@ -55,7 +55,7 @@ REQUIREMENTS = {
     "sortedcontainers>=1.4.4": ["sortedcontainers"],
     "pysaml2>=3.0.0": ["saml2"],
     "pymacaroons-pynacl>=0.9.3": ["pymacaroons"],
-    "msgpack-python>=0.3.0": ["msgpack"],
+    "msgpack-python>=0.4.2": ["msgpack"],
     "phonenumbers>=8.2.0": ["phonenumbers"],
     "six>=1.10": ["six"],