[1.6.x] Fixed #22317 -- Fixed documented handler400 default value
[1.6.x] Fixed #22317 -- Fixed documented handler400 default value

Backport of 3f7615cddc from master.

django-nonrel/django,django-nonrel/django,felixjimenez/django,redhat-openstack/django,django-nonrel/django,redhat-openstack/django,felixjimenez/django,redhat-openstack/django,django-nonrel/django,felixjimenez/django,redhat-openstack/django,felixjimenez/django