Add a simple check at start-up to make sure the directory exists for the calibration mode json files.
Add a simple check at start-up to make sure the directory exists for
the calibration mode json files.

tobeycarman/dvm-dos-tem,tobeycarman/dvm-dos-tem,tobeycarman/dvm-dos-tem,tobeycarman/dvm-dos-tem,tobeycarman/dvm-dos-tem,tobeycarman/dvm-dos-tem