gitignore: add ".Dockerfile-functional-tester"
gitignore: add ".Dockerfile-functional-tester"

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

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