Update fonb-setup.py

i have updated the parser. At first its just removing the existing content with sed command and then echo-ing the simple lines, as discussed. 
As mentioned earlier as well, i couldn't replicate the exact bug, in normal conditions, thus it only malfunctions under abnormalities. The scenario, i imagined was when the key/value settings varies, the config parser was adding an '=' at the end. Since the parser is not working now, all it does is adds the sample lines in place.