do not call get_empty_query_set, that's deprecated

wiki/managers.py

@@ -3,6 +3,7 @@ from __future__ import unicode_literals
 from django.db import models
 from django.db.models import Q
 from django.db.models.query import QuerySet, EmptyQuerySet
+from django import VERSION as DJANGO_VERSION
 
 from mptt.managers import TreeManager
 
@@ -41,6 +42,18 @@ class ArticleQuerySet(QuerySet):
         return self.filter(current_revision__deleted=False)
 
 
+class ArticleEmptyQuerySet(EmptyQuerySet):
+    
+    def can_read(self, user):
+        return self
+    
+    def can_write(self, user):
+        return self
+
+    def active(self):
+        return self
+
+    
 class ArticleFkQuerySetMixin():
 
     def can_read(self, user):
@@ -98,8 +111,15 @@ class ArticleFkEmptyQuerySet(ArticleFkEmptyQuerySetMixin, EmptyQuerySet):
 
 
 class ArticleManager(models.Manager):
-
+    
     def get_empty_query_set(self):
+        # Pre 1.6 django, we needed a custom inheritor of EmptyQuerySet
+        # to pass custom methods. However, 1.6 introduced that EmptyQuerySet
+        # cannot be instantiated but instead passes through the methods
+        # of the custom QuerySet.
+        # See: https://code.djangoproject.com/ticket/22817
+        if DJANGO_VERSION < (1, 6):
+            return ArticleEmptyQuerySet(self.model, using=self._db)
         return self.get_query_set().none()
 
     def get_query_set(self):