r12804: This patch reworks the Samba4 sockets layer to use a socket_address

r12804: This patch reworks the Samba4 sockets layer to use a socket_address
structure that is more generic than just 'IP/port'.

It now passes make test, and has been reviewed and updated by
metze. (Thankyou *very* much).

This passes 'make test' as well as kerberos use (not currently in the
testsuite).

The original purpose of this patch was to have Samba able to pass a
socket address stucture from the BSD layer into the kerberos routines
and back again.   It also removes nbt_peer_addr, which was being used
for a similar purpose.

It is a large change, but worthwhile I feel.

Andrew Bartlett
(This used to be commit 88198c4881d8620a37086f80e4da5a5b71c5bbb2)