The Reload method cannot just be invoked on the administrative DBus
object. Just like the method for reloading specific units, it needs
to be invoked on the proper DBus service, addressing the proper object
and using the right interface.
Added an additional constant for the systemd DBus service. Even though
it shares the same value as the interface base name, this is
happenstance and it's technically incorrect to open a connection to an
interface name. The connection needs a service name.
Fixes#509
191a2495a5