Code review comment for lp:~lool/linaro-image-tools/missing-sbin

I've pushed a quite different approach now; the bad part is that the hwpack testsuite doesn't pass anymore when PATH is broken, this is because the hwpack code uses subprocess.Popen directly.

What I would propose is that we convert the hwpack code to use cmd_runner.

I also need to add tests for sanitize_path, but wouldn't mind some feedback on the overall approach.