Update libkv dependency

vendor/golang.org/x/net/idna/punycode.go

@@ -1,4 +1,6 @@
-// Copyright 2012 The Go Authors. All rights reserved.
+// Code generated by running "go generate" in golang.org/x/text. DO NOT EDIT.
+
+// Copyright 2016 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
@@ -7,7 +9,6 @@ package idna
 // This file implements the Punycode algorithm from RFC 3492.
 
 import (
-	"fmt"
 	"math"
 	"strings"
 	"unicode/utf8"
@@ -27,6 +28,8 @@ const (
 	tmin        int32 = 1
 )
 
+func punyError(s string) error { return &labelError{s, "A3"} }
+
 // decode decodes a string as specified in section 6.2.
 func decode(encoded string) (string, error) {
 	if encoded == "" {
@@ -34,7 +37,7 @@ func decode(encoded string) (string, error) {
 	}
 	pos := 1 + strings.LastIndex(encoded, "-")
 	if pos == 1 {
-		return "", fmt.Errorf("idna: invalid label %q", encoded)
+		return "", punyError(encoded)
 	}
 	if pos == len(encoded) {
 		return encoded[:len(encoded)-1], nil
@@ -50,16 +53,16 @@ func decode(encoded string) (string, error) {
 		oldI, w := i, int32(1)
 		for k := base; ; k += base {
 			if pos == len(encoded) {
-				return "", fmt.Errorf("idna: invalid label %q", encoded)
+				return "", punyError(encoded)
 			}
 			digit, ok := decodeDigit(encoded[pos])
 			if !ok {
-				return "", fmt.Errorf("idna: invalid label %q", encoded)
+				return "", punyError(encoded)
 			}
 			pos++
 			i += digit * w
 			if i < 0 {
-				return "", fmt.Errorf("idna: invalid label %q", encoded)
+				return "", punyError(encoded)
 			}
 			t := k - bias
 			if t < tmin {
@@ -72,7 +75,7 @@ func decode(encoded string) (string, error) {
 			}
 			w *= base - t
 			if w >= math.MaxInt32/base {
-				return "", fmt.Errorf("idna: invalid label %q", encoded)
+				return "", punyError(encoded)
 			}
 		}
 		x := int32(len(output) + 1)
@@ -80,7 +83,7 @@ func decode(encoded string) (string, error) {
 		n += i / x
 		i %= x
 		if n > utf8.MaxRune || len(output) >= 1024 {
-			return "", fmt.Errorf("idna: invalid label %q", encoded)
+			return "", punyError(encoded)
 		}
 		output = append(output, 0)
 		copy(output[i+1:], output[i:])
@@ -121,14 +124,14 @@ func encode(prefix, s string) (string, error) {
 		}
 		delta += (m - n) * (h + 1)
 		if delta < 0 {
-			return "", fmt.Errorf("idna: invalid label %q", s)
+			return "", punyError(s)
 		}
 		n = m
 		for _, r := range s {
 			if r < n {
 				delta++
 				if delta < 0 {
-					return "", fmt.Errorf("idna: invalid label %q", s)
+					return "", punyError(s)
 				}
 				continue
 			}