fix train upload bug
fix train upload bug

watson-developer-cloud/visual-recognition-nodejs,oremari/plantDiseaseSymptoms-vr-demo-1483744992341,filipmadej/visual-recognition-demo,watson-developer-cloud/visual-recognition-nodejs,oremari/plantDiseaseSymptoms-vr-demo-1483744992341,filipmadej/visual-recognition-demo