Updating an upload ignores errors

Updating the status (or otherwise) of an upload on click-updown from sca ignores errors (models.py:ClickPackageUpload.update_upload (used to be set_status)).

This means that the web interface will tell you you've successfully published, the click index will be updated with the download url, but no one will be able to download it.

There's a TODO in the code saying as much "This should be async, with retries".

As we get more apps, we could potentially have a lot of inconsistent state.