Support systemd template service unit files

This pull request fixes too issues:

1. There is a compilation error when trying to run the service module on a systemd system in --check mode.

2. The service module's systemd logic does not permit usage with template unit files.  For an example, it is unable to manage the WOL service as described at https://wiki.archlinux.org/index.php/Wake-on-LAN#With_systemd