Code review comment for lp:~mluto/mailman/qrunnersleep

Please explain what the need for this is. Normally, Mailman/Queue/Runner.py will sleep for QRUNNER_SLEEP_TIME after running _oneloop() if there are no more files in the queue.

Further, your change is only executed when bin/qrunner is run manually with --runner=All which is not the normal way to run all the runners. When they are run via bin/mailmanctl, bin/qrunner is called separately for each runner slice and the "Fast track for one infinite runner" code is executed.