bugfix for "IOError: [Errno 2] No such file or directory: '/data/project/drtrigonbot/pywikibot-compat/externals/jseg/externals/pydmtx/externals/pycolorname/PMS_cal-print.pkl'"

Change-Id: I085ffed30e355e299b5a5b86c69b5247beabed74