fixed query result __len__ (more efficient)
fixed query result __len__ (more efficient)

armandobs14/rdflib,dbs/rdflib,RDFLib/rdflib,avorio/rdflib,ssssam/rdflib,yingerj/rdflib,marma/rdflib,dbs/rdflib,ssssam/rdflib,yingerj/rdflib,yingerj/rdflib,ssssam/rdflib,ssssam/rdflib,armandobs14/rdflib,marma/rdflib,RDFLib/rdflib,RDFLib/rdflib,dbs/rdflib,marma/rdflib,avorio/rdflib,armandobs14/rdflib,RDFLib/rdflib,marma/rdflib,armandobs14/rdflib,dbs/rdflib,avorio/rdflib,avorio/rdflib,yingerj/rdflib