Fixed systemd service script. Added config path and config-test=true. Also added enviroment file for CentOS/RedHat, that is put to /etc/sysconfig. For Debian, that is /etc/defaults(systemd.service also needs path change)

Init script now reads config dir location from /etc/sysconfig/log-courier file
Merge branch 'develop' of https://github.com/matejzero/log-courier into develop