Update the related object widgets for some Django 1.11 changes.

Review Request #10486 — Created April 1, 2019 and submitted — Latest diff uploaded


Review Board


The related object widgets call build_attrs in order to create some
attributes to pass into the HTML for the widgets. Django's changed the
signature for this method since Django 1.6, which led to some crashes
during rendering.

The function itself is really simple in its purpose, so rather than
working around the changes, we just build the attributes dictionary in
the widget directly, fixing that compatibility problem.

Unit tests pass on Django 1.6 and 1.11 (with other in-progress changes).