Code review comment for lp:~doanac/linaro-image-tools/slash-proc-spam-version2

This looks fine but the new run_local_atexit_funcs() code uses the sys module which is not available in hwpack.py, which means not all code paths of run_local_atexit_funcs() are tested. I'll see if I can add a test for the missing path but otherwise I'll just add the missing import and merge.