Fixes #3995 - Add backup of cron file rudder-agent and restoration by check-rudder-agent
Merge pull request #138 from nperron/bug_3995/int/backup_cron_file_of_rudder_agent_to_permit_restoration

Fixes #3995 - Add backup of cron file rudder-agent and restoration by check-rudder-agent
Merge branch 'branches/rudder/2.6' into branches/rudder/2.7