Return an urllib2 opener with the useragent already set in the appropriate
    way.

def make_invenio_opener(component=None):
    """
    Return an urllib2 opener with the useragent already set in the appropriate
    way.
    """
    opener = urllib2.build_opener()
    opener.addheaders = [('User-agent', make_user_agent_string(component))]
    return opener