Implement gateway support Google Cloud Storage

vendor/cloud.google.com/go/internal/version/update_version.sh

@@ -0,0 +1,6 @@
+#!/bin/bash
+
+today=$(date +%Y%m%d)
+
+sed -i -r -e 's/const Repo = "([0-9]{8})"/const Repo = "'$today'"/' $GOFILE
+

vendor/cloud.google.com/go/internal/version/version.go

@@ -0,0 +1,71 @@
+// Copyright 2016 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.
+
+//go:generate ./update_version.sh
+
+// Package version contains version information for Google Cloud Client
+// Libraries for Go, as reported in request headers.
+package version
+
+import (
+	"runtime"
+	"strings"
+	"unicode"
+)
+
+// Repo is the current version of the client libraries in this
+// repo. It should be a date in YYYYMMDD format.
+const Repo = "20170404"
+
+// Go returns the Go runtime version. The returned string
+// has no whitespace.
+func Go() string {
+	return goVersion
+}
+
+var goVersion = goVer(runtime.Version())
+
+const develPrefix = "devel +"
+
+func goVer(s string) string {
+	if strings.HasPrefix(s, develPrefix) {
+		s = s[len(develPrefix):]
+		if p := strings.IndexFunc(s, unicode.IsSpace); p >= 0 {
+			s = s[:p]
+		}
+		return s
+	}
+
+	if strings.HasPrefix(s, "go1") {
+		s = s[2:]
+		var prerelease string
+		if p := strings.IndexFunc(s, notSemverRune); p >= 0 {
+			s, prerelease = s[:p], s[p:]
+		}
+		if strings.HasSuffix(s, ".") {
+			s += "0"
+		} else if strings.Count(s, ".") < 2 {
+			s += ".0"
+		}
+		if prerelease != "" {
+			s += "-" + prerelease
+		}
+		return s
+	}
+	return ""
+}
+
+func notSemverRune(r rune) bool {
+	return strings.IndexRune("0123456789.", r) < 0
+}