Include ooxmlexport_setup.mk only once in Module_sw.mk,
so that gbuildtojson can properly set last included
makefile for test jsons.

Change-Id: Ie8ed3296ae97cf4a33d652599673f389b224993e
Reviewed-on: https://gerrit.libreoffice.org/32502Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Matúš Kukan <matus@libreoffice.org>