GCE/Windows: add cluster-location to instance metadata

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Author: yujuhong

cluster/gce/windows/node-helper.sh

@@ -19,6 +19,7 @@
 function get-windows-node-instance-metadata-from-file {
   local metadata=""
   metadata+="cluster-name=${KUBE_TEMP}/cluster-name.txt,"
+  metadata+="cluster-location=${KUBE_TEMP}/cluster-location.txt,"
   metadata+="kube-env=${KUBE_TEMP}/windows-node-kube-env.yaml,"
   metadata+="kubelet-config=${KUBE_TEMP}/windows-node-kubelet-config.yaml,"
   # To get startup script output run "gcloud compute instances