support run example.sh with buildin spark (#1661)
support run example.sh with buildin spark (#1661)


qiuxin2012/BigDL,yiheng/BigDL,wzhongyuan/BigDL,zhangxiaoli73/BigDL,luchy0120/BigDL,wzhongyuan/BigDL,yiheng/BigDL,luchy0120/BigDL,zhangxiaoli73/BigDL,i8run/BigDL-1,wzhongyuan/BigDL,jenniew/BigDL,qiuxin2012/BigDL,i8run/BigDL-1,jenniew/BigDL,yiheng/BigDL,luchy0120/BigDL,zhangxiaoli73/BigDL,qiuxin2012/BigDL,i8run/BigDL-1,jenniew/BigDL