Check the executor config file for consistency.

def check_config(config):
    '''
        Check the executor config file for consistency.
    '''
    # Check server URL
    url = config.get("Server", "url")
    try:
        urlopen(url)
    except Exception as e:
        logger.error(
            "The configured OpenSubmit server URL ({0}) seems to be invalid: {1}".format(url, e))
        return False
    # Check directory specification
    targetdir = config.get("Execution", "directory")
    if platform.system() is not "Windows" and not targetdir.startswith("/"):
        logger.error(
            "Please use absolute paths, starting with a /, in your Execution-directory setting.")
        return False
    if not targetdir.endswith(os.sep):
        logger.error(
            "Your Execution-directory setting must end with a " + os.sep)
        return False
    return True