More logging when we decide to time out a slave.

Summary:
They're timing out much more often than I'd expect -- even when we're
doing back-to-back deploys they are timing out.  Not sure why.  I am
hoping this logging will shed some light.

Test Plan: Fingers crossed.

Reviewers: chris

Reviewed By: chris

Differential Revision: http://phabricator.khanacademy.org/D11464