Fixed Postfix >= 2.10 relay issue, disabled Dovecot auth debugging

* Postfix >= 2.10 added the "smtpd_relay_restrictions" option
  which controls relay behavior. If this is unset, relays to
  outside destinations will fail with an SMTP 554 5.7.1
* Dovecot authentication debugging was left on; it is now
  disabled
Need to use reject_unauth_destination or mail gets bounced...