Rudder

If we have CFEngine installed, with up to date policies from the masterfiles (at least, newer than 3.6), and we install rudder-agent, policies from agent are erased
Indeed, check rudder agent checks for file /var/cfengine/inputs/common/1.0/update.cf , and if it's not there, it purges the promises, to replace by rudder initial promises

We need to have a finer detection of invalid files (most probably, check if policies in cfengine folder are distributed by Rudder, or managed by something else)