Fix wrong case statement in master.sh

docs/getting-started-guides/docker-multinode/master.sh

@@ -121,6 +121,7 @@ start_k8s(){
             fi
             ifconfig docker0 down
             yum -y -q install bridge-utils && brctl delbr docker0 && systemctl restart docker
+        ;;
         ubuntu|debian)
             DOCKER_CONF="/etc/default/docker"
             echo "DOCKER_OPTS=\"\$DOCKER_OPTS --mtu=${FLANNEL_MTU} --bip=${FLANNEL_SUBNET}\"" | sudo tee -a ${DOCKER_CONF}