e2e: fix range indexing for args2env conversion
e2e: fix range indexing for args2env conversion

Was dropping the last argument in the slice.

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