etcdserver: remove 2.0 StatusNotFound version check
etcdserver: remove 2.0 StatusNotFound version check

ajityagaty/etcd,sebrandon1/etcd,bdarnell/etcd,YuleiXiao/etcd,whuwxl/etcd,ajityagaty/etcd,akauppi/etcd,a-robinson/etcd,mkumatag/etcd,vimalk78/etcd,xiang90/etcd,whuwxl/etcd,gyuho/etcd,rnaveiras/etcd,glevand/coreos--etcd,YuleiXiao/etcd,mkumatag/etcd,li-ang/etcd,lorneli/etcd,yudai/etcd,etcd-io/etcd,xiang90/etcd,mickep76/etcd,mqliang/etcd,rnaveiras/etcd,heyitsanthony/etcd,sebrandon1/etcd,cockroachdb/etcd,etcd-io/etcd,vimalk78/etcd,mqliang/etcd,sinsharat/etcd,plasticbox/etcd,li-ang/etcd,coreos/etcd,armstrongli/etcd,bdarnell/etcd,visheshnp/etcd,plasticbox/etcd,gyuho/etcd,lorneli/etcd,joshix/etcd,etcd-io/etcd,fanminshi/etcd,mickep76/etcd,mkumatag/etcd,bluebreezecf/etcd,mqliang/etcd,bluebreezecf/etcd,akauppi/etcd,joshix/etcd,visheshnp/etcd,armstrongli/etcd,a-robinson/etcd,yudai/etcd,fanminshi/etcd,heyitsanthony/etcd,cockroachdb/etcd,dannysauer/etcd,ajityagaty/etcd,coreos/etcd,glevand/coreos--etcd,sinsharat/etcd,dannysauer/etcd,rnaveiras/etcd