Division by zero in BS440csv.py about bs440

[Boldfor]

@aeff81, not sure whether I know what I'm doing ;) but I added a PR for this bug (creatvty#2) which fixed it for me.

@creatvty, please have a look.

[Boldfor]

This is not only relevant for „guest users“, and also not limited to the .csv-plugin (am using the mqtt-plugin): I have the BS 444, and sometimes the „user detection“ fails (or does not even start), which results in „only weight being sent“ (with everything else being blank). Also in these (multiple) cases they script stops with „division by 0“.

Traceback (most recent call last):
  File "/home/pi/BS440-HA-AD/BS440.py", line 332, in <module>
    appendBmi(persondata[0]['size'], weightdata)
  File "/home/pi/BS440-HA-AD/BS440.py", line 122, in appendBmi
    element['bmi'] = round(element['weight'] / (size * size), 1)
ZeroDivisionError: float division by zero

[Boldfor]

@aeff81, is merged and should be fixed. Maybe you can check and close the issue.