Update vendor directory

Re-added cobra patch 499475bb41

vendor/google.golang.org/appengine/internal/identity_classic.go

@@ -0,0 +1,27 @@
+// Copyright 2015 Google Inc. All rights reserved.
+// Use of this source code is governed by the Apache 2.0
+// license that can be found in the LICENSE file.
+
+// +build appengine
+
+package internal
+
+import (
+	"appengine"
+
+	netcontext "golang.org/x/net/context"
+)
+
+func DefaultVersionHostname(ctx netcontext.Context) string {
+	return appengine.DefaultVersionHostname(fromContext(ctx))
+}
+
+func RequestID(ctx netcontext.Context) string  { return appengine.RequestID(fromContext(ctx)) }
+func Datacenter(_ netcontext.Context) string   { return appengine.Datacenter() }
+func ServerSoftware() string                   { return appengine.ServerSoftware() }
+func ModuleName(ctx netcontext.Context) string { return appengine.ModuleName(fromContext(ctx)) }
+func VersionID(ctx netcontext.Context) string  { return appengine.VersionID(fromContext(ctx)) }
+func InstanceID() string                       { return appengine.InstanceID() }
+func IsDevAppServer() bool                     { return appengine.IsDevAppServer() }
+
+func fullyQualifiedAppID(ctx netcontext.Context) string { return fromContext(ctx).FullyQualifiedAppID() }