Removes unused custom Exception handler.
Removes unused custom Exception handler.

ronalcc/zipline,humdings/zipline,mattcaldwell/zipline,euri10/zipline,semio/zipline,stkubr/zipline,bartosh/zipline,StratsOn/zipline,sketchytechky/zipline,zhoulingjun/zipline,dhruvparamhans/zipline,AlirezaShahabi/zipline,grundgruen/zipline,alphaBenj/zipline,CarterBain/AlephNull,keir-rex/zipline,CDSFinance/zipline,wubr2000/zipline,davidastephens/zipline,CDSFinance/zipline,cmorgan/zipline,magne-max/zipline-ja,MonoCloud/zipline,jimgoo/zipline-fork,wilsonkichoi/zipline,dhruvparamhans/zipline,otmaneJai/Zipline,chrjxj/zipline,stkubr/zipline,umuzungu/zipline,gwulfs/zipline,alphaBenj/zipline,kmather73/zipline,magne-max/zipline-ja,ChinaQuants/zipline,nborggren/zipline,wubr2000/zipline,sketchytechky/zipline,dmitriz/zipline,enigmampc/catalyst,florentchandelier/zipline,gwulfs/zipline,zhoulingjun/zipline,Scapogo/zipline,erikness/AlephOne,euri10/zipline,dmitriz/zipline,mattcaldwell/zipline,semio/zipline,kmather73/zipline,jordancheah/zipline,iamkingmaker/zipline,wilsonkichoi/zipline,ronalcc/zipline,jimgoo/zipline-fork,bartosh/zipline,dkushner/zipline,florentchandelier/zipline,morrisonwudi/zipline,cmorgan/zipline,AlirezaShahabi/zipline,YuepengGuo/zipline,iamkingmaker/zipline,quantopian/zipline,humdings/zipline,aajtodd/zipline,joequant/zipline,jordancheah/zipline,DVegaCapital/zipline,enigmampc/catalyst,erikness/AlephOne,StratsOn/zipline,umuzungu/zipline,michaeljohnbennett/zipline,MonoCloud/zipline,Scapogo/zipline,YuepengGuo/zipline,dkushner/zipline,aajtodd/zipline,ChinaQuants/zipline,morrisonwudi/zipline,joequant/zipline,chrjxj/zipline,nborggren/zipline,keir-rex/zipline,CarterBain/AlephNull,otmaneJai/Zipline,quantopian/zipline,michaeljohnbennett/zipline,davidastephens/zipline,DVegaCapital/zipline,grundgruen/zipline