#2183 JSBSim: /enignes/engine[*]/n{1,2} not replayable

At least /enignes/engine[*]/n{1,2} can not be replayed if the jet engine exists (don't know for other engine types).

Most likely a related: they can not be overwritten by any JSBSim filter, as described in https://github.com/JSBSim-Team/jsbsim/issues/210

Far as I remember, the problem already existed in 3.x