ExitPolicyRejectPrivate now rejects more local addresses by default:
 * the relay's published IPv6 address (if any), and
 * any publicly routable IPv4 or IPv6 addresses on any local interfaces.

This resolves a security issue for IPv6 Exits and multihomed Exits that
trust connections originating from localhost.

Resolves ticket 17027. Patch by "teor".
Patch on 42b8fb5a (11 Nov 2007), released in 0.2.0.11-alpha.