Code review comment for lp://staging/~nuclearbob/utah/bug1073617

I fixed the formatting. The problem with the test cases is that when we switch to the user nobody, we're losing the directory we're currently in, so commands that are supposed to run relative to that directory are failing. I'm not sure of the best way to get around that. I tried prepending a cd to the cwd passed into run_cmd, but that doesn't seem to be helping.