Revert "Fixes #3995 - Add backup of /etc/{init.d,default,cron.d}/rudder-agent in preinst and restore action in check-rudder-agent cron file"

This reverts commit 63978b96a8ac9e4fc915973806c28844e64d3360.
Fixes #3997 - Add backup of /etc/{init.d,default}/rudder-agent in preinst and restore action in check-rudder-agent cron file
Merge pull request #137 from nperron/bug_3997/int/prevent_from_removing_init_and_default_of_rudder_agent

Fixes #3997 - Add backup of /etc/{init.d,default}/rudder-agent in preinst and restore action in check-rudder-agent cron file
Merge branch 'branches/rudder/2.4' into branches/rudder/2.6
Merge branch 'branches/rudder/2.6' into branches/rudder/2.7