HTTPretty messes with the return values of `socket.getaddrinfo`
to make it return local addresses, as well as a few other things.
Rather than try to monkeypatch around monkeypatches, simply
disable blacklisting when HTTPretty's monkeypatches are detected.

Obviously, this means that you won't get blacklisting when you're
using HTTPretty for mocking in your tests. Too bad!