Refactor test_logging to use unittest. This should finally solve the flakiness
issues.

Thanks to Antoine Pitrou for the patch.
diff --git a/Misc/ACKS b/Misc/ACKS
index 794b1f4..f7a08d4 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -524,6 +524,7 @@
 François Pinard
 Zach Pincus
 Michael Piotrowski
+Antoine Pitrou
 Michael Pomraning
 Iustin Pop
 John Popplewell