Bug#877992: Info received (postfix: Postfix does not start services after upgrade to stretch 9.2 and reboot)

[Daniel Haid]

I use the following temoporary fix for a default instance only setup, which 
will persist across reboots:

ln -s /lib/systemd/system/postfix@.service 
/etc/systemd/system/postfix.service.wants/postfix@-.service