caljsoncheckfunctions.py: fix bug with finding delta N organic.
caljsoncheckfunctions.py: fix bug with finding delta N organic.

had been using current - current, instead of current - previous.

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