Added Console Logging to HaaS

This patch adds console logging to HaaS by running ipmitool subprocesses that
log to files.  There is now an API call 'show_console' that displays the
contents of the console log to the user.  Log files are securely deleted when
nodes have a change in ownership.
>This would be a good thing to wrap up in a helper method on the node. look at Headnode._vmname() for a reference.

I don't know what you mean, but I'll take a look and see if I can figure it out.

> Additionally, we need to be more concious with our decision of where to actual put the logs -- the current directory is almost certainly the wrong answer in production. Somewhere under /var/run might be the right one.

Okay, I will implement this change.