suzerain: avoid dropping /radial_nozzle everywhere

This snippet

    // However, if noz was provided, match its contents to other members
    if (noz) {
        if (scenario && (boost::math::isnan)(noz->gam0))
            noz->gam0 = scenario->gamma;
    }

was causing default radial_nozzle_definitions to be non-trivial
and appear in output files needlessly.

git-svn-id: https://svn.ices.utexas.edu/repos/pecos/suzerain/trunk@42587 0bd85f0b-c151-43b9-a1e9-27231104551f
suzerain: some corrections to two-point correlations document

git-svn-id: https://svn.ices.utexas.edu/repos/pecos/suzerain/trunk@42588 0bd85f0b-c151-43b9-a1e9-27231104551f
suzerain: #2503 init baseflow_map with radial_nozzle

git-svn-id: https://svn.ices.utexas.edu/repos/pecos/suzerain/trunk@42589 0bd85f0b-c151-43b9-a1e9-27231104551f