INCR-265 Run python-modernize on lms/djangoapps/courseware/management and lms/djangoapps/courseware/tests (#20716)

* updated files according to INCR-265

* fixed docstring and line-length problems from quality test

* Revert "fixed docstring and line-length problems from quality test"

This reverts commit d050f55a4ecfaa38f46b80ec4bb85ff399a79a8c.

* fixed errors reported in quality report

* had error, fixed it

* reversed change

* fixed over/under indentation, and added line to import.py that Ned had suggested

* tried disabling pylint for this line

* testing new email

* testing email in different window

* re-added symlink and docstring

lms/djangoapps/courseware/tests/test_context_processor.py

@@ -1,6 +1,8 @@
 """
 Unit tests for courseware context_processor
 """
+from __future__ import absolute_import
+
 from django.contrib.auth.models import AnonymousUser
 from mock import Mock