Updated mail/postfix to 2.6.5

The stable release Postfix 2.6.5 addresses the defects described
below (some already addressed with the not-announced Postfix 2.6.3
release).  These defects are also addressed in the legacy releases
that are still maintained: Postfix 2.5.9, 2.4.13 and 2.3.19.

Do not use Postfix 2.6.4, 2.5.8, 2.4.12, 2.3.18, 2.7-20090807, and
2.7-20090807-nonprod.  These contain a DNS workaround that causes
more trouble than it prevents. It is removed until further notice.

Defects fixed with Postfix 2.6.3, 2.5.9, 2.4.13 and 2.3.19:

- The Postfix Milter client got out of step with a Milter application
  after the application sent a "quarantine" request at end-of-message
  time. The Milter application would still be in the end-of-message
  state, while Postfix would already be working on the next SMTP
  event, typically, QUIT or MAIL FROM. In the latter case, Milter
  responses for the previously-received email message would be
  applied towards the next MAIL FROM transaction.  This problem was
  diagnosed with help from Alban Deniz.

Defects fixed with Postfix 2.6.5, 2.5.9, 2.4.13 and 2.3.19:

- The Postfix SMTP server would abort with an "unexpected lookup
  table" error when an SMTPD policy server was mis-configured in a
  particular way.


(martti)