vendor: move golang.org/x/net/http2/hpack back to vendor

Updates #14047

Change-Id: I7e314e2c7e3e8da18ab023729740fbc9ea3f661e
Reviewed-on: https://go-review.googlesource.com/21063
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

src/go/build/build_test.go

@@ -300,7 +300,6 @@ func TestShellSafety(t *testing.T) {
 }
 
 func TestImportVendor(t *testing.T) {
-	t.Skip("skipping; hpack has moved to internal for now; golang.org/issue/14047")
 	testenv.MustHaveGoBuild(t) // really must just have source
 	ctxt := Default
 	ctxt.GOPATH = ""

src/go/build/deps_test.go

@@ -358,7 +358,7 @@ var pkgDeps = map[string][]string{
 		"L4", "NET", "OS",
 		"compress/gzip", "crypto/tls", "mime/multipart", "runtime/debug",
 		"net/http/internal",
-		"internal/golang.org/x/net/http2/hpack",
+		"golang.org/x/net/http2/hpack",
 	},
 	"net/http/internal": {"L4"},
 

src/net/http/h2_bundle.go

 // Code generated by golang.org/x/tools/cmd/bundle.
-//go:generate bundle -o h2_bundle.go -prefix http2 -import golang.org/x/net/http2/hpack=internal/golang.org/x/net/http2/hpack golang.org/x/net/http2
+//go:generate bundle -o h2_bundle.go -prefix http2 golang.org/x/net/http2
 
 // Package http2 implements the HTTP/2 protocol.
 //
@@ -24,7 +24,6 @@ import (
 	"encoding/binary"
 	"errors"
 	"fmt"
-	"internal/golang.org/x/net/http2/hpack"
 	"io"
 	"io/ioutil"
 	"log"
@@ -39,6 +38,8 @@ import (
 	"strings"
 	"sync"
 	"time"
+
+	"golang.org/x/net/http2/hpack"
 )
 
 // ClientConnPool manages a pool of HTTP/2 client connections.

src/vendor/README

-This file needs to exist because the vendor directory needs
-to exist for some go/build tests to pass, and git can't track
-empty directories.
-
-In Go 1.7 we'll use this directory again. (In Go 1.6 we tried but
-reverted).
-
-See http://golang.org/issue/14047 for details.