* Fix error handling test
#2569 introduced a bug in the test. The test never passed but because travis-ci lovingly broke the integration we had a long time ago the tests weren't run in CI until I merged. So, this fixes the tests & does a better job cleaning up the query in an errored state.
* Update sponsors
It’s missing `co.wrap`, so it doesn’t actually run (Mocha does nothing with the paused generator). The test group that follows it, “using an ended pool”, covers the same thing anyway.
