Get bridgedb back to using bulkexitlist
bridgedb uses bulkexitlist to recognize when a user is coming from a Tor exit, so it's harder to enumerate the address-based pool just by coming through Tor.
But we have varied over the past year which list we use, since the main bulkexitlist was flaky.
When I was last the maintainer for bridgedb, I had a cron running on moria1 to generate an exitlist, and I had bridgedb fetch it via wget periodically. Are we still doing that, or did we move to something else? Now that the new check seems more stable, we should consider moving back to the main source.