This test failed since d240785b on devstack.
The self.request_factory.get() just return a request object, which is
being passed to views.course_about() directly without being processed by
edxmako.middleware. The REQUEST_CONTEXT.request in
https://github.com/edx/edx-platform/blob/d240785b17bdcaeb11e4ef24ee4a3697da26c9b4/common/djangoapps/edxmako/middleware.py#L39
is None, instead of request object, which contains the LANGUAGE_CODE and
other stuff used by the view.

Also cleaned up the use of MakoMiddleware. Using the method in
edxmako.tests module.