Log Message:
Update from version 2.11nb1 to 2.12.

Upstream changes:

Authen-SASL 2.12 -- Mon Jun 30 21:35:21 CDT 2008

Enhancements
  * GSSAPI implement protocol according to RFC, but by default,
    remain compatible with cyrus sasl lib
  * DIGEST-MD5 implement channel encryption layer