Comment 23 for bug 1594740

@nacc With regards to the other way to answer your question, I've now also tested the following sequence of events:

1. Purged the supervisor package,
2. removed the PPA `nacc/lp1594740',
3. ran `apt-get update',
4. ensured the symbolic link /etc/systemd/system/multi-user.target.wants/supervisor.service doesn't exist (indeed it doesn't, as expected),
5. reinstalled the supervisor package from Ubuntu's official repository (verified using `apt-cache policy supervisor'),
6. checked if the Supervisor daemon was started (it wasn't, because I just installed the buggy package),
7. ran `systemctl enable supervisor && systemctl start supervisor' as the documented workaround (this started and enabled the Supervisor daemon as expected),
7. reactivated the PPA `nacc/lp1594740',
8. ran `apt-get update && apt-get install supervisor', this upgraded the supervisor package to the version from the PPA.

After step 8 the Supervisor daemon has been restarted (its PID has changed, as I would expect from an upgrade to a package that contains a system daemon) but during the upgrade there were no conflicts, warnings or complaints about Supervisor having already been manually enabled previously. Again, this looks good to me!