Handle early Responses

[willstott101]

Responses can be returned by middleware before reaching AuthenticationMiddleware - in these cases there is no request.user attribute.

This happens with Django's default MIDDLEWARE ordering if the current host is disallowed (not in ALLOWED_HOSTS) for instance.

[btimby]

Looks good, can you think of a way to add a unit test? I skimmed over the tests and did not see anything similar. This may require a new TestCase that tests the middleware class directly.

[btimby]

For reference, these views are used by some of the tests:

https://github.com/smartfile/django-session-jwt/blob/master/django_session_jwt/views.py

And the tests themselves are here, at the top of the file are some low-level tests (mocks and method calls). Tests for the middleware would fit roughly into this category. The second section uses the views above.

https://github.com/smartfile/django-session-jwt/blob/master/django_session_jwt/tests.py

[willstott101]

Added a test that fails before this patch

[willstott101]

Moved the test to the existing ViewTestCase as that's the level it's operating at right now