libre/iceweasel: Drop origin params from DDG search
    
    These let DuckDuckGo know the place in UI the search ran from. For
    example, the resulting search URL from address bar:
    
    https://html.duckduckgo.com/html/?t=ffab&q=parabola
    
    where t=ffab is the parameter in question. See unpatched file in
    the source tree for possible values of this parameter:
    
    browser/components/search/extensions/ddg/manifest.json