cubicweb #4842333 DataFeedParser.retrieve_url is passing wrong headers parameter to urllib2.Request [validation pending]

This headers parameter is set to None in DataFeedParser.retrieve_url signature. urllib2.Request expects an iterable and won't check for None.

prioritynormal
typebug
done in3.20.2
load0.500
load left0.000
closed by#2eb06486273a [datafeed] Set headers parameter to an empty dict in DataFeedParser.retrieve_url
patch[datafeed] Set headers parameter to an empty dict in DataFeedParser.retrieve_url [applied]