Update global config from YAML file

    If fn is None, looks in global config directory, which is either defined
    by the INTAKE_CONF_DIR env-var or is ~/.intake/ .

def load_conf(fn=None):
    """Update global config from YAML file

    If fn is None, looks in global config directory, which is either defined
    by the INTAKE_CONF_DIR env-var or is ~/.intake/ .
    """
    if fn is None:
        fn = cfile()
    if os.path.isfile(fn):
        with open(fn) as f:
            try:
                conf.update(yaml_load(f))
            except Exception as e:
                logger.warning('Failure to load config file "{fn}": {e}'
                               ''.format(fn=fn, e=e))