Switch the "check updates required" middleware to use process_view.
The introduction of apply_to for media bundles was interfering with the updates

required middleware. In particular, what was happening was that we tried to

render a template from the process_request method of a middleware, which

happens before HttpRequest.resolver_match is set. This is easily fixed by using

process_view instead, which is probably more correct for this middleware anway.
This problem exhibited itself when running the

testManualUpdatesRequiredBadUpload unit test. I've checked all our other

middlewares to make sure that none of them are trying to render responses from

process_request.

Ran unit tests.