Return a nice and uniform user-agent string to be used when Invenio
    act as a client in HTTP requests.

def make_user_agent_string(component=None):
    """
    Return a nice and uniform user-agent string to be used when Invenio
    act as a client in HTTP requests.
    """
    ret = "Invenio-%s (+%s; \"%s\")" % (cfg.get('CFG_VERSION'),
                                        cfg.get('CFG_SITE_URL'), cfg.get('CFG_SITE_NAME'))
    if component:
        ret += " %s" % component
    return ret