cubicweb #3025537 NoneX uris displayed in default RDF view [open]

See the snippet below (cw_source / owned_by / created_by):

<rdf:Description rdf:about="http://orion:8080/740">
  <cw:owned_by rdf:resource="None6"/>
  <cw:possede rdf:resource="http://orion:8080/741"/>
  <cw:created_by rdf:resource="None6"/>
  <cw:creation_date rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">2013-07-18T16:45:21.530447</cw:creation_date>
  <cw:cw_source rdf:resource="None1"/>
  <cw:numero rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">1234</cw:numero>
  <cw:modification_date rdf:datatype="http://www.w3.org/2001/XMLSchema#dateTime">2013-07-18T16:49:18.026665</cw:modification_date>
  <rdf:type rdf:resource="http://ns.cubicweb.org/cubicweb/0.0/Client"/>
</rdf:Description>
prioritynormal
typebug
done in<not specified>
closed by<not specified>