Update userparameter_systemd_services.conf

[Josephvh]

Service discovery SED for search and replace of ".service" syntax didn't target only ".service", _service is also targeted and incorrectly reports on a service called mail_directory_service. E.G

~ # systemctl list-unit-files | grep service | grep enabled | awk '{print $1}'| sed 's/.service//' | grep mail_dir mail_directory.service ~ # systemctl list-unit-files | grep service | grep enabled | awk '{print $1}'| sed 's/.service//' | grep mail_dir mail_directory_service