* Fix#526: fatal: no SASL authentication mechanisms
When using the container with SMTP_ONLY = 1, then the container fails
on ehlo because there is no valid sasl authentication mechanism
available. This happens because sasl has been enabled within
postfix/main.cf per default but sasl is not configured.
To fix this _setup_postfix_sasl does not depend anymore on
ENABLE_SASLAUTHD and will check in it's logic, whether to enable sasl
or not within postfix/main.cf.
* Fix#526: fatal: no SASL authentication mechanisms
When using the container with SMTP_ONLY = 1, then the container fails
on ehlo because there is no valid sasl authentication mechanism
available. This happens because sasl has been enabled within
postfix/main.cf per default but sasl is not configured.
To fix this _setup_postfix_sasl does not depend anymore on
ENABLE_SASLAUTHD and will check in it's logic, whether to enable sasl
or not within postfix/main.cf.
* Fix test
