[Mate]mdm.service ExecStop/ExecReload refer to non-existent files

[Pheeble]

Linux Mint 18 Mate (new installation)

journalctl (with persistence) always reports errors for mdm.service in logs from previous boots:

ie. the command 'journalctl -b -1 -p "err"' produces:
 systemd[4412]: mdm.service: Failed at step EXEC spawning /usr/sbin/mdm-stop: No such file or directory

The mdm systemd service file '/lib/systemd/system/mdm.service' includes the lines:
 ExecReload=/usr/sbin/mdm-restart
 ExecStop=/usr/sbin/mdm-stop

Neither '/usr/sbin/mdm-restart' or '/usr/sbin/mdm-stop' exist, resulting in the journalctl error messages.

Possible solutions:

1. Remove the ExecReload and ExecStop lines from /lib/systemd/system/mdm.service, or override with /etc/systemd/system/mdm.service.d/override.conf containing the lines:
 ExecReload=
 ExecStop=

2. Create symlinks /usr/sbin/mdm-restart->/dev/null and /usr/sbin/mdm-stop->/dev/null

3. Create executable files (scripts?) /usr/sbin/mdm-restart and /usr/sbin/mdm-stop that read their respective actions from configuration files, eg. mdm-restart.conf and mdm-stop.conf.