Dockerfile-test: use ubuntu 16.10 as base image
Dockerfile-test: use ubuntu 16.10 as base image

Debian base image from golang-stretch was breaking
shellcheck tests.

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

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