"Form" is not allowed as a column name

[Mike Blyth]

Upgrading an old app that used "form" for a column name, I got an error from AS. It turns out that helpers/list_column_helpers.rb#get_column_value
starts looking for a “form_column” method, while that name happens to be aliased to FormColumnHelpers:: active_scaffold_input_for, causing a mess.