Fix an issue that sometimes underlying DataFlow job fails but DataflowJob does not report error. (#286)
Fix an issue that sometimes underlying DataFlow job fails but DataflowJob does not report error. (#286)


googledatalab/pydatalab,craigcitro/pydatalab,jdanbrown/pydatalab,craigcitro/pydatalab,jdanbrown/pydatalab,parthea/pydatalab,supriyagarg/pydatalab,googledatalab/pydatalab,googledatalab/pydatalab,parthea/pydatalab,supriyagarg/pydatalab,craigcitro/pydatalab,yebrahim/pydatalab,parthea/pydatalab,yebrahim/pydatalab,jdanbrown/pydatalab,yebrahim/pydatalab,supriyagarg/pydatalab