twitter/commons — pull request #332 by zmanji (2014-11-07 02:49:23+00:00)
Title: Remove unnecessary atexit handler for tearing down ssh processes/

I have noticed that the TunnelHelper class reference in the `_cleanup` function can be `None` when executed. This causes an exception and therefore fails to kill the opened ssh processes. This patch changes the approach taken to avoid the `_cleanup` function entirely and still achieve the same results.