remove redundant file exists check
remove redundant file exists check

TOCTOU

This check is already done when cmdline_parser try to open the file

KeelanArrendale/zmap,djeraseit/zmap,scarito/zmap-android,zhuyue1314/zmap,scarito/zmap,3L3N4/zmap,cicku/zmap,eacha/zmap,zhuyue1314/zmap,shakenetwork/zmap,djeraseit/zmap,tdi/zmap,tdi/zmap,unixfreaxjp/zmap,tdi/zmap,tdi/zmap,shakenetwork/zmap,tdi/zmap,scarito/zmap,scarito/zmap,scarito/zmap-android,coolacid/zmap,cicku/zmap,3L3N4/zmap,unixfreaxjp/zmap,potatozhao/zmap,unixfreaxjp/zmap,scarito/zmap-android,coolacid/zmap,potatozhao/zmap,KeelanArrendale/zmap,shakenetwork/zmap,zhuyue1314/zmap,djeraseit/zmap,zmap/zmap,3L3N4/zmap,scarito/zmap,eacha/zmap,cicku/zmap,unixfreaxjp/zmap,willscott/zmap,cicku/zmap,eacha/zmap,shakenetwork/zmap,cicku/zmap,zhuyue1314/zmap,potatozhao/zmap,potatozhao/zmap,3L3N4/zmap,KeelanArrendale/zmap,coolacid/zmap,eacha/zmap,shakenetwork/zmap,BobuSumisu/zmap,zhuyue1314/zmap,djeraseit/zmap,BobuSumisu/zmap,KeelanArrendale/zmap,potatozhao/zmap,willscott/zmap,scarito/zmap,3L3N4/zmap,unixfreaxjp/zmap,BobuSumisu/zmap,zmap/zmap,scarito/zmap-android,djeraseit/zmap,coolacid/zmap,BobuSumisu/zmap,willscott/zmap,eacha/zmap,willscott/zmap,willscott/zmap,KeelanArrendale/zmap,BobuSumisu/zmap,zmap/zmap,coolacid/zmap