redis-sessions: fixed cleanup command failing on serialized errors.

somehow beaker mangles the data when logout happens we cannot de-serialize it properly then

rhodecode/lib/user_sessions.py

@@ -21,7 +21,9 b' import re'
 import time
 import datetime
 import dateutil
+import dateutil.relativedelta
 import pickle
+import base64
 
 from rhodecode.model.db import DbSession, Session
 
@@ -199,6 +201,7 b' class RedisAuthSessions(BaseAuthSessions'
         import redis
         args = {
             'socket_timeout': 60,
+            'decode_responses': False,
             'url': self.config.get('beaker.session.url')
         }
 
@@ -217,14 +220,21 b' class RedisAuthSessions(BaseAuthSessions'
         client = self._get_client()
         expiry_time = time.time() - older_than_seconds
         deleted_keys = 0
+
         for key in client.keys('beaker_cache:*'):
             data = client.get(key)
             if data:
-                json_data = pickle.loads(data)
+                accessed_time = 0
+                data = base64.b64decode(data)
+
                 try:
+                    json_data = pickle.loads(data)
                     accessed_time = json_data['_accessed_time']
+                except pickle.UnpicklingError:
+                    accessed_time = 0
                 except KeyError:
                     accessed_time = 0
+
                 if accessed_time < expiry_time:
                     client.delete(key)
                     deleted_keys += 1