[datafeed parser] fix retrieve_url to always return urllib2.urlopen compatible output as one should expect to be able to call geturl/getcode/info on the returned object whatever the url he gave. Related to #3682069

if versions_map['cubicweb'][0] == (3, 7, 4):
    config['http-session-time'] *= 60
    config['cleanup-session-time'] *= 60
    config['cleanup-anonymous-session-time'] *= 60