remove unused code in XYZ sg importer
remove unused code in XYZ sg importer

MengjiaoH/ospray,ospray/OSPRay,MengjiaoH/ospray,MengjiaoH/ospray,ospray/OSPRay,ospray/OSPRay,MengjiaoH/ospray,wilsonCernWq/ospray,wilsonCernWq/ospray,wilsonCernWq/ospray,MengjiaoH/ospray,ospray/OSPRay