Coveralls isn't solid enough

[bagder]

I did this

I've tried to rely on coveralls to tell us data about test coverage. It keeps reporting ridiculous numbers and very often shows bogus red warnings like this:

(screenshot from #4692 - the coverage was never 81% so this claimed 7% decrease is a complete lie)

I expected the following

Reliable info. As this works now, I think it typically does more harm than good: it generates red builds completely arbitrary and even when green the numbers it shows are then hard to trust.

Action

The test coverage is valuable information but changes very rarely. We could probably change the coveralls to get run in a cronjob somewhere every now and then instead. I intend to switch it off from the CI system due to its "unreliablity".

[dfandrich]

There's at least one other code coverage tool I've seen used in projects: https://github.com/marketplace/codecov I have no idea if it's appropriate for curl, though.