toc-nesting-merge: Set positions to 0 when deleting
toc-nesting-merge: Set positions to 0 when deleting

Apparently fields can't be blank, even when being deleted

olivierdalang/django-nested-admin,sbussetti/django-nested-admin,sbussetti/django-nested-admin,olivierdalang/django-nested-admin,sbussetti/django-nested-admin,olivierdalang/django-nested-admin