hack/scripts-dev: use Go 1.9.3 by default
hack/scripts-dev: use Go 1.9.3 by default

Signed-off-by: Gyuho Lee <3454051ee3341eb69bdf6fca40899cdad4d86496@gmail.com>

joshix/etcd,glevand/coreos--etcd,rnaveiras/etcd,cockroachdb/etcd,mkumatag/etcd,rnaveiras/etcd,coreos/etcd,etcd-io/etcd,sinsharat/etcd,whuwxl/etcd,mkumatag/etcd,mkumatag/etcd,rnaveiras/etcd,whuwxl/etcd,bdarnell/etcd,li-ang/etcd,ajityagaty/etcd,gyuho/etcd,heyitsanthony/etcd,etcd-io/etcd,mqliang/etcd,cockroachdb/etcd,etcd-io/etcd,vimalk78/etcd,li-ang/etcd,fanminshi/etcd,vimalk78/etcd,xiang90/etcd,fanminshi/etcd,sebrandon1/etcd,heyitsanthony/etcd,ajityagaty/etcd,lorneli/etcd,mqliang/etcd,coreos/etcd,dannysauer/etcd,ajityagaty/etcd,joshix/etcd,sebrandon1/etcd,sinsharat/etcd,lorneli/etcd,xiang90/etcd,dannysauer/etcd,mqliang/etcd,bdarnell/etcd,glevand/coreos--etcd,gyuho/etcd