Previously, we had an issue where we'd treat an unknown address as
0, which turned into "0.0.0.0", which looked like a rejected
address. This meant in practice that as soon as we started doing
comparisons of unknown uint32 addresses to short policies, we'd get
'rejected' right away. Because of the circumstances under which
this would be called, it would only happen when we had local DNS
cached entries and we were looking to launch new circuits.
