light-locker-command -l exits with success, if the light-locker is not running

[Jarno Suni]

It should exit with non-zero, as `xscreensaver-command -lock` does in similar case, as it fails to lock.

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: light-locker 1.6.0-4ubuntu1
ProcVersionSignature: Ubuntu 4.2.0-23.28-generic 4.2.6
Uname: Linux 4.2.0-23-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.19.1-0ubuntu5
Architecture: amd64
CurrentDesktop: XFCE
Date: Wed Jan 20 17:40:01 2016
EcryptfsInUse: Yes
InstallationDate: Installed on 2015-11-21 (59 days ago)
InstallationMedia: Xubuntu 15.10 "Wily Werewolf" - Release amd64 (20151021)
SourcePackage: light-locker
UpgradeStatus: No upgrade log present (probably fresh install)

[Jarno Suni (jarnos)]

This bug also implies that (current) xflock4 fails to lock, but still exits with 0, if xscreensaver is not running and light-locker is not running, but is installed.

[Jarno Suni (jarnos)]

Separate bug report for xfce4-session: Bug #1537507

[Theo Linkspfeifer (lastonestanding)]

Works fine in 18.04 which ships with the latest light-locker version.

==============
Version 1.8.0
==============

- Build against newer systemd
- Added information for debugging
- Proper exit codes for light-locker-command
- Translations update