Fix hardcoded attribute in form

[patriciomacadden]

In the _form partial, when the generated attribute is attachments, it generates a file_field with multiple: true. The error checking bits (to display colored borders) are hardcoded to password instead of attribute.column_name.

[flavorjones]

Ah, we both missed this in af38df9. Thank you for fixing!

[patriciomacadden]

yeah, my mistake! Thanks 😄