[krbdev.mit.edu #8348] Remove workaround when binding to udp addresses and pktinfo isn't supported by the system

[Sarah Day via RT]

Currently if the system doesn't support pktinfo and kadmind or krb5kdc 
are binding to a upd address the system krb5 binds to all the local 
addresses. Currently most systems support pktinfo, so the workaround 
isn't really required anymore. Removing the workaround will only affect 
systems that don't have pktinfo support and have multiple NICs and are 
listening on a wildcard address. Users with this setup may specify each 
of the local addresses directly that kadmind or krb5kdc should listen on 
in kdc.conf.