Fix for the selection of the model-free models to be optimised.
This problem was found by Michael in the thread starting at https://mail.gna.org/public/relax-devel/2010-02/msg00004.html (Message-id: <4B689504.2040601@...>).
Authored by: bugman 2010-02-02
Parent: [r10621]
Child: [r10623]