[krbdev.mit.edu #3306] kdc sends udp replies from wrong addresses, does not listen on loopback interface

[Ken Raeburn via RT]

I've just checked in a patch to the KDC, loosely based on the patch from Denis.  (See ticket 5517 
in RT.)  Briefly tested on Mac OS X and Linux.

I don't want to touch the RPC code until we figure out the API problems, so I'll leave this ticket 
open...