Commit 8a6e859 wrongly introduced this new field when adding the new
`payment_authorize` module.
As 8.0 is a [stable version](http://git.io/vfACM), no data model change
is allowed.
We convert this field to a `fields.dummy` in case someone installed (or
update) this module with this fields to ensure the view still applied
and is not broken.
dd84e612d0