Comment 1 for bug 1199913

It also spams the log file because it cannot find "lxc-ls".
Which causes that task to return an error, causing the runner to kill off the machiner environ-provider, apiserver upgrader and firewaller.
And then restart them, only to kill them, ad nauseum.

I don't think this is the same bug as https://bugs.launchpad.net/juju-core/+bug/1199915
But it is what I'm seeing right now trying to upgrade juju-core bootstrapped with 1.10 => trunk (using trunk)