Avoid form errors when hidden sort_order is not filled in.
Avoid form errors when hidden sort_order is not filled in.

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