Un-prune code-generator scripts

Scripts under code-generator are required to generate code when
snapshot APIs are changed. Therefore they should not be pruned.

vendor/k8s.io/code-generator/cmd/go-to-protobuf/protoc-gen-gogo/main.go

@@ -0,0 +1,32 @@
+/*
+Copyright 2015 The Kubernetes Authors.
+
+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.
+*/
+
+// Package main defines the protoc-gen-gogo binary we use to generate our proto go files,
+// as well as takes dependencies on the correct gogo/protobuf packages for godeps.
+package main
+
+import (
+	"github.com/gogo/protobuf/vanity/command"
+
+	// dependencies that are required for our packages
+	_ "github.com/gogo/protobuf/gogoproto"
+	_ "github.com/gogo/protobuf/proto"
+	_ "github.com/gogo/protobuf/sortkeys"
+)
+
+func main() {
+	command.Write(command.Generate(command.Read()))
+}