Set manager_inheritance_from_future for Django 1.11 projects.
Set manager_inheritance_from_future for Django 1.11 projects.

This avoids getting warnings from polymorphic 2.0.1 that detects and
fixes manager inheritance issues for Django 1.11

django-fluent/django-fluent-contents,edoburu/django-fluent-contents,django-fluent/django-fluent-contents,edoburu/django-fluent-contents,edoburu/django-fluent-contents,django-fluent/django-fluent-contents