Support systemd service file

I create a script to generate systemd service file and create it when run ```make``` command.
And, I add lines to spec file to install the service file.
> I found %{_unitdir} macro on "/usr/lib/rpm/macros.d/macros.systemd" file in CentOS7 environment.

I fix it at 7ff8b7c revision.

> In addition, please use install command instead of cp to set permission properly.

I fix it at a55e11c revision.