courier-mta systemd service file won't load because of syntax errors in it

[rsevero]

After upgrading from 16.04 to 16.10 my courier installation wasn't working anymore.

I found out the following error messages with "systemctl status courier-mta.service":

Jun 07 18:11:10 h1-df systemd[1]: [/lib/systemd/system/courier-mta.service:3] Failed to add dependency on courier-authdaemon.service,courier.service,courierfilter.service, ignoring: Invalid argument
Jun 07 18:11:10 h1-df systemd[1]: [/lib/systemd/system/courier-mta.service:4] Failed to add dependency on courier-authdaemon.service,courier.service,courierfilter.service, ignoring: Invalid argument

I found out that there is a syntax error at lines 3 and 4. They read:

Requires=courier-authdaemon.service,courier.service,courierfilter.service
After=courier-authdaemon.service,courier.service,courierfilter.service

when they should read:

Requires=courier-authdaemon.service courier.service courierfilter.service
After=courier-authdaemon.service courier.service courierfilter.service

Notice that the correct versions have spaces separating the various options in each line and not commas as the wrong one has.

ProblemType: Bug
DistroRelease: Ubuntu 16.10
Package: courier-mta 0.76.1-3 [modified: lib/systemd/system/courier-mta.service]
ProcVersionSignature: Ubuntu 4.8.0-54.57-generic 4.8.17
Uname: Linux 4.8.0-54-generic x86_64
ApportVersion: 2.20.3-0ubuntu8.3
Architecture: amd64
Date: Wed Jun 7 18:15:48 2017
InstallationDate: Installed on 2016-05-09 (394 days ago)
InstallationMedia: Ubuntu-Server 15.10 "Wily Werewolf" - Release amd64 (20151021)
ProcEnviron:
 LANGUAGE=en_US:en
 TERM=screen
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: courier
UpgradeStatus: Upgraded to yakkety on 2017-06-06 (1 days ago)
modified.conffile..etc.courier.courierd: [modified]
modified.conffile..etc.courier.esmtpd-ssl: [modified]
mtime.conffile..etc.courier.courierd: 2017-06-06T09:27:57.036179
mtime.conffile..etc.courier.esmtpd-ssl: 2017-06-06T12:13:10.888307