Fix bulk deletion of ContentItem objects
Fix bulk deletion of ContentItem objects

Collector runs through the relation.bulk_related_objects for
GenericRelation objects, which fails on polymorphic queries.
Returning the non_polymorphic query instead.

pombredanne/django-fluent-contents,edoburu/django-fluent-contents,pombredanne/django-fluent-contents,jpotterm/django-fluent-contents,django-fluent/django-fluent-contents,jpotterm/django-fluent-contents,ixc/django-fluent-contents,pombredanne/django-fluent-contents,ixc/django-fluent-contents,django-fluent/django-fluent-contents,edoburu/django-fluent-contents,jpotterm/django-fluent-contents,django-fluent/django-fluent-contents,edoburu/django-fluent-contents,ixc/django-fluent-contents