* kdc_util.c (): Added new helper functions

* kdc_util.c (): Added new helper functions
	dbentry_has_key_for_enctype(), dbentry_supports_enctype(), and
	select_session_keytype().

* kdc_preauth.c: Added support for the ENC_TIMESTAMP preauthentication
	scheme.

* do_tgs_req.c (process_tgs_req): Fixed the keytype/enctype selection
	criteria for the server key, and the ticket session key.

* do_as_req.c (process_as_req): Added calls to the kdc preauthentication
	verification routines.  Fixed the keytype/enctype selection
	criteria for the client key, the server key, and the ticket
	session key.

* main.c (finish_realm): Make sure all parts of the realm structure are
	freed properly.
	(main): Free the kcontext krb5_context.

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@7058 dc483132-0cff-0310-8789-dd5450dbe970