sparqlUpdate: restore early bail-out
sparqlUpdate: restore early bail-out

nicola/rdflib.js,nicola/rdflib.js,timbl/rdflib.js,ariutta/rdflib.js,redaktor/rdflib.js,ariutta/rdflib.js,redaktor/rdflib.js,timbl/rdflib.js,timbl/rdflib.js,ariutta/rdflib.js