Skip erroneous configuration messages

[tomkooij]

If number of messages > MAX_NUMBER_OF_CONFIGS (100): Treat configs as erroneous and skip. (Leave in raw datastore, but do not import new configs)

This should prevent #182 from happening again.

[153957]

Good idea.
We do need to make these kinds of errors in the hisparc-update more loud. Now they can go by unnoticed. Easiest might be to also print error logs to stderr, which can be mailed to us when they occur in the cron job..

[tomkooij]

Yes, I like that:

• Use stdout as logger stream in hisparc-update.py, redirect that to /var/log/hisparc.log in the cron job.
• add extra logger at loglevel error to stderr. cron should mail that.