Fixes #5937: enforce content of ncf conf file from techniques

I don't understand. I don't see any copy below.

The files in /usr/share/ncf/ are the standard distribution of ncf. They should never be modified. Consider them as the framework source - you just download it and use it, then update it when necessary.

Any use we make of ncf happens in /var/rudder/configuration-repository/ncf. This is the "instance" folder for ncf - this is where we put anything local, specific to this usage of ncf (configuration, generic_methods, techniques, etc).