[models] Minor simplification in update_all
[models] Minor simplification in update_all

interop-dev/django-netjsongraph,interop-dev/django-netjsongraph,netjson/django-netjsongraph,netjson/django-netjsongraph,netjson/django-netjsongraph,interop-dev/django-netjsongraph,netjson/django-netjsongraph