Pep8 fixes of django_comment_client code

lms/djangoapps/django_comment_client/base/tests.py

lms/djangoapps/django_comment_client/base/views.py

lms/djangoapps/django_comment_client/forum/views.py

.../django_comment_client/management/commands/assign_role.py

..._comment_client/management/commands/reload_forum_users.py

...go_comment_client/management/commands/show_permissions.py

lms/djangoapps/django_comment_client/models.py

lms/djangoapps/django_comment_client/tests.py

lms/djangoapps/django_comment_client/tests/test_helpers.py

lms/djangoapps/django_comment_client/tests/test_models.py

...apps/django_comment_client/tests/test_mustache_helpers.py

lms/djangoapps/django_comment_client/utils.py