Fixes #3995 - Add backup of cron file rudder-agent (again!) into rudder-agent preinst
Merge pull request #149 from nperron/bug_3995/int/prevent_from_removing_init_default_and_cron_file_of_rudder_agent_AGAIN

Fixes #3995 - Add backup of cron file rudder-agent (again!) into rudder-agent preinst