Determine whether a given file is one of the files created by setup_container_system_config().
    @param file: Absolute file path as string.

def is_container_system_config_file(file):
    """Determine whether a given file is one of the files created by setup_container_system_config().
    @param file: Absolute file path as string.
    """
    if not file.startswith("/etc/"):
        return False
    return file in [os.path.join("/etc", f.decode()) for f in CONTAINER_ETC_FILE_OVERRIDE]