Reduced unnecessary verbosity

The intention is that vulcan is run automatically at a high frequency.
To make that useful for running in cron jobs, we really only want to output
something if there was a problem.
Security Improvement - Set lifetime for ssh-agent key

ssh-add now sets a (shortish) lifetime for added keys.  This should
reduce the likelihood of a key being added and then sitting in the
agent until some nefarious user comes along...