Clean out a template temp file

def __clean_tmp(sfn):
    '''
    Clean out a template temp file
    '''
    if sfn.startswith(os.path.join(tempfile.gettempdir(),
                                   salt.utils.files.TEMPFILE_PREFIX)):
        # Don't remove if it exists in file_roots (any saltenv)
        all_roots = itertools.chain.from_iterable(
                six.itervalues(__opts__['file_roots']))
        in_roots = any(sfn.startswith(root) for root in all_roots)
        # Only clean up files that exist
        if os.path.exists(sfn) and not in_roots:
            os.remove(sfn)