Silence 90% of remaining Django 1.8 model warnings.

mayan/apps/common/classes.py

@@ -1,5 +1,6 @@
 from __future__ import unicode_literals
 
+from django.apps import apps
 from django.core.exceptions import PermissionDenied
 from django.db import models
 from django.utils.translation import ugettext
@@ -125,7 +126,9 @@ class Filter(object):
         return unicode(self.label)
 
     def get_queryset(self, user):
-        from acls.models import AccessControlList
+        AccessControlList = apps.get_model(
+            app_label='acls', model_name='AccessControlList'
+        )
 
         queryset = self.model.objects.all()
         for kwargs in self.filter_kwargs: