Code review comment for lp:~abentley/juju-ci-tools/industrial-test

Is this summarise the try-finally issue correct? As we know know there is a chance that the old-client error can be swallowed by a new client error. When investigate an exception destroying the new-client we need to be mindful of an exception from old-client is missing. Maybe we can address this issue in the future by adding an additional logging step after each destroy to indicate that the old-client did destroy itself.