Fix bug 1109289

The only problem with this change is that if an event has a vidly_template but not a vidlysubmission things can go wrong but I don't know if such situation is possible
The next test `test_event_without_vidly_hd_download_links` is a bit repetitive. You could just carry on the first `test_event_with_vidly_hd_download_links` and after you've done these four `ok_(...)` tests, you just set ```
vidly_submission.hd = False
vidly_submission.save()

response = self.client.get(url)
...
```