Fixed #11302 -- Avoid unnesscary (and possibly unintentional) queries…

…/results from generic inline formsets.

When an instance with no primary key value is passed in to a generic inline
formset we ensure no queries/results occur. Thanks Alex Gaynor.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@10981 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/contrib/contenttypes/generic.py

@@ -317,7 +317,7 @@ def get_default_prefix(cls):
     def get_queryset(self):
         # Avoid a circular import.
         from django.contrib.contenttypes.models import ContentType
-        if self.instance is None:
+        if self.instance is None or self.instance.pk is None:
             return self.model._default_manager.none()
         return self.model._default_manager.filter(**{
             self.ct_field.name: ContentType.objects.get_for_model(self.instance),