suzerain: #2998 grossly correct twopoint_kz

This gets the scaling factors correct, though I still
may have an issue with Nyquist handling.  Getting there.

git-svn-id: https://svn.ices.utexas.edu/repos/pecos/suzerain/trunk@44710 0bd85f0b-c151-43b9-a1e9-27231104551f