Cleanup leftovers for Debian without systemd

This is a combination that isn't supported since years, we can get rid
of the code.

Author: bastelfreak

manifests/params.pp

@@ -296,10 +296,6 @@
     }
   } else {
     case $facts['os']['family'] {
-      'Debian': {
-        $agent_restart_command = "/usr/sbin/service ${service_name} reload"
-        $unavailable_runmodes = ['systemd.timer']
-      }
       'Windows': {
         $agent_restart_command = undef
         $unavailable_runmodes = ['cron', 'systemd.timer']