Rudder

So far, the list of nodes a server should share the promise to are defined by a "magic" variable in the system directive "common-policy-server-uuid"
However, with the relay, this system doesn't work well: the variables are correct, but not on the right nodes :(

Root has the directive common-root
Relay has the directive common-root
Node under relay has the directive common-relay

So relay don't have the proper directive, hence not the right value

We can easily replace this magical mechanism by standard system variable :
- MANAGED_NODES
- MANAGED_NODES_id

there will be 3 subtickets, one for the techniques, one for cf-clerk, and on for rudder