Fix django-browserid for Django 1.9 with Jinja2

[Uberi]

• The context processor is missing in the source, but present in the wheel. This PR adds it back with slight modifications.
• The context processor passes the request as the first parameter, but helpers.browserid_info doesn't take any parameters. This results in obscure errors when using the library. Removing the functools.partial solves the issue.

[Osmose]

Thanks for the PR!

So it's not that the context processor is missing in the source, it's that it was removed a long time ago and I hadn't cleaned out my build directory since then while making releases, which mucked up the wheel. I've pushed out a new 2.0.1 release with a clean build that doesn't have the file.

As for Django 1.9, there's no docs for using django-browserid with Django 1.9, and I hesitate to bother writing them since Persona is being shut down at the end of this year, but AFAIK the only thing missing from the current install steps is making sure the browserid_info and other helpers are available within your Jinja templates. I don't know how to do this for Django's built-in Jinja support, but here's an example of how to configure it using django-jinja (specifically the globals options).

So I'm closing this, but hopefully that's enough for you to get things working temporarily before moving off of Persona.