added copy.sh which cuts the client repo; made necessary changes to scripts in

the repo to cope with the client repo staging area; added symlink
vendor/k8s.io/client-go which pointed to the staging area.

hack/update-codecgen.sh

@@ -31,6 +31,7 @@ generated_files=($(
       \( \
         -wholename './output' \
         -o -wholename './_output' \
+        -o -wholename './staging' \
         -o -wholename './release' \
         -o -wholename './target' \
         -o -wholename '*/third_party/*' \