[datafeed] don't allow arbitrary kwargs on DatafeedParser initializer
else they will be handled nicely by appobject base class, while we rather want an
error in the case of a source parser (arguable).
usr/lib/python2*/*-packages/cubicweb/web
usr/lib/python2*/*-packages/cubicweb/wsgi
usr/share/cubicweb/cubes/shared/data
usr/share/cubicweb/cubes/shared/wdoc