sa-update: use the same decision logic as in spamd for choosing IO::Socket::IP vs
  IO::Socket::INET6, prefer the former for consistency, let the underlying module
  pick the right address family instead of forcing it through local_address();
  added some debugging and cosmetics



git-svn-id: https://svn.apache.org/repos/asf/spamassassin/trunk@1471605 13f79535-47bb-0310-9956-ffa450edef68