Touch up gitignore to only exclude root /dist dir
Touch up gitignore to only exclude root /dist dir

yiheng/BigDL,i8run/BigDL-1,yiheng/BigDL,qiuxin2012/BigDL,luchy0120/BigDL,qiuxin2012/BigDL,JerryYanWan/BigDL,i8run/BigDL-1,yiheng/BigDL,jenniew/BigDL,122689305/BigDL,122689305/BigDL,wzhongyuan/BigDL,luchy0120/BigDL,jenniew/BigDL,JerryYanWan/BigDL,jenniew/BigDL,122689305/BigDL,wzhongyuan/BigDL,sethah/BigDL,luchy0120/BigDL,i8run/BigDL-1,psyyz10/BigDL,qiuxin2012/BigDL,wzhongyuan/BigDL,zhangxiaoli73/BigDL,psyyz10/BigDL,JerryYanWan/BigDL,sethah/BigDL,sethah/BigDL,zhangxiaoli73/BigDL,zhangxiaoli73/BigDL,psyyz10/BigDL