Allow level param in Django SentryHandler.__init__

[gthb]

For consistency with superclass and with logging.Handler

[xordoquy]

I'm a bit curious about the use case that lead to this change.

[coveralls]

Coverage remained the same when pulling bc5fa08 on gthb:fix-handler-init-missing-level-param into 4efb80e on getsentry:master.

[gthb]

I was troubleshooting the fact that my use of logger.error(..., extra={'request': request}) was not working (no request information made it through), and found that I was initializing logging with this:

from raven.handlers.logging import SentryHandler
handler = SentryHandler(raven_client, level=logging.ERROR)

whereas I needed the Django-specific handler to get the extra={'request': request} handled. So I just changed the import to from raven.contrib.django.handlers import SentryHandler ... but then the call fails because the level parameter is invalid. That inconsistency seems unnecessary, hence this change.

[xordoquy]

Ok, thanks :)