mit-kdb: support MIT Kerberos 1.16 KDB API changes

mit-kdb: support MIT Kerberos 1.16 KDB API changes

MIT Kerberos 1.16 adds ability to audit local and remote addresses
during AS_REQ processing. As result, audit_as_req callback signature
was changed to include the addresses and KDB API version was increased.

Change mit-kdb code to properly expose audit_as_req signature KDC
expects in 1.16 version. Also update #ifdefs to account for the new
KDB API version.

This commit does not add actual audit of the local and remote IP
addresses, it only makes it possible to compile against MIT Kerberos
1.16.

Signed-off-by: Alexander Bokovoy <ab@samba.org>
Reviewed-by: Andreas Schneider <asn@samba.org>
Autobuild-User(master): Andreas Schneider <asn@cryptomilk.org>
Autobuild-Date(master): Fri Jan 19 01:36:22 CET 2018 on sn-devel-144