Removed a remaining Django < 1.6 code branch.

polymodels/models.py

@@ -1,6 +1,5 @@
 from __future__ import unicode_literals
 
-import django
 from django.contrib.contenttypes.models import ContentType
 from django.core.exceptions import ImproperlyConfigured
 from django.db import models
@@ -102,14 +101,7 @@ def prepare_polymorphic_model(sender, **kwargs):
             parent = parents.pop(0)
             if issubclass(parent, BasePolymorphicModel):
                 parent_opts = parent._meta
-                # We can't do `select_related` on multiple one-to-one
-                # relationships on django < 1.6
-                # see https://code.djangoproject.com/ticket/16572 and
-                # https://code.djangoproject.com/ticket/13781
-                if django.VERSION < (1, 6):
-                    lookup = LOOKUP_SEP.join(attrs[0:1])
-                else:
-                    lookup = LOOKUP_SEP.join(attrs)
+                lookup = LOOKUP_SEP.join(attrs)
                 parent_opts._subclass_accessors[sender] = (tuple(attrs), proxy, lookup)
                 if parent_opts.proxy:
                     parents.insert(0, parent_opts.proxy_for_model)