django-not-configured is an error raised by pylint (with
the pylint-django plugin) when it's not correctly configured.
We should not be applying lint amnesty for such a violation.
By explicitly importing the legacy namespace classes, we make it clear
that we are using soon-to-be-deprecated classes. We will then be able to
start removing the legacy classes, one module at a time.
* uses openedx waffle_utils instead of straight waffle
* adds student.STUDENT_WAFFLE_NAMESPACE
* improves comment
Also changed the waffle switch to use _ instead of . to respect current conventions.
