pull up r19062 from trunk

pull up r19062 from trunk

 r19062@cathode-dark-space:  jaltman | 2007-01-15 23:18:02 -0500
 ticket: 5349
 tags: pullup

   This commit adds two new functions, krb5_server_decrypt_ticket_keyblock
   (private) and krb5_server_decrypt_ticket_keytab (public).  These
   functions take a krb5_ticket as input and decrypt it using the provided
   key data.  The public function is useful for higher level application
   protocols such a TLS-KRB5 and AFS RX-KRB5 which exchange a service
   but do not use the AP-REQ/AP-REP messages.

   This commit also adds new functionality to kvno which permits kvno
   when provided a keytab as input to verify whether or not the keytab
   contains a key that can successfully decrypt the obtains service ticket.

ticket: 5349

git-svn-id: svn://anonsvn.mit.edu/krb5/branches/krb5-1-6@19160 dc483132-0cff-0310-8789-dd5450dbe970