finish the multinode ubuntu k8s setup script and guide ,tested ok

cluster/ubuntu-cluster/reconfigureDocker.sh

@@ -0,0 +1,33 @@
+#!/bin/bash
+
+# Copyright 2015 Google Inc. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# script to reconfigue the docker daemon network settings 
+
+# Run as root only
+if [ "$(id -u)" != "0" ]; then
+    echo >&2 "Please run as root"
+    exit 1
+fi
+
+ip link set dev docker0 down
+brctl delbr docker0
+
+source /run/flannel/subnet.env
+
+echo DOCKER_OPTS=\"-H tcp://127.0.0.1:4243 -H unix:///var/run/docker.sock \
+    --bip=${FLANNEL_SUBNET} --mtu=${FLANNEL_MTU}\" > /etc/default/docker
+
+service docker restart