Nagios check for task queue pileup doesn't appear flag superevent worker going down
The nagios check added in !1016 (merged) doesn't appear to fix the problem we were hoping it fixed, namely that the superevent worker can just silently stop working (see #491 for hypothesis as to why this happens). Superevents stopped being created at around 645 UTC on Dec 11, but nagios thought everything was fine nearly 14 hours later.