Fixes #5846: Use portable init handling in system Techniques

Ticket: http://www.rudder-project.org/redmine/issues/5846

To be merged in 3.0
shouldn't it be
(root_server|process_exception_on_relay)::
"start_process" usebundle => service_ensure_running("${initscript}"),
ifvarclass => "!forced_trigger_${canoname}";

(root_server|process_exception_on_relay)::
"start_process" usebundle => service_restart("${initscript}"),
ifvarclass => "forced_trigger_${canoname}";