Comment 16 for bug 1595096

OK, looks like the minimal fix for Xenial might be:
https://git.launchpad.net/postfix/commit/?h=stable/v3.1&id=89c5899a0702919d92c616c071fce60a5cb764fd
https://git.launchpad.net/postfix/commit/?h=stable/v3.1&id=3694fc38119480ac6312299d43b8bcd453332133

Quick build & test:
root@x1:/home/ubuntu# postmulti -e init
root@x1:/home/ubuntu# postmulti -I postfix-example -G mta -e create
root@x1:/home/ubuntu# postmulti -l
- - y /etc/postfix
postfix-example mta n /etc/postfix-example

, seems happy enough. Latest debian (and zesty) has even nicer systemd integration; cool, but too invasive for SRUing.