go.crypto: use golang.org/x/... import paths

LGTM=bradfitz
R=rsc, bradfitz
CC=golang-codereviews
https://golang.org/cl/167190043

nacl/box/box.go

@@ -18,9 +18,9 @@ This package is interoperable with NaCl: http://nacl.cr.yp.to/box.html.
 package box
 
 import (
-	"code.google.com/p/go.crypto/curve25519"
-	"code.google.com/p/go.crypto/nacl/secretbox"
-	"code.google.com/p/go.crypto/salsa20/salsa"
+	"golang.org/x/crypto/curve25519"
+	"golang.org/x/crypto/nacl/secretbox"
+	"golang.org/x/crypto/salsa20/salsa"
 	"io"
 )
 

nacl/box/box_test.go

@@ -10,7 +10,7 @@ import (
 	"encoding/hex"
 	"testing"
 
-	"code.google.com/p/go.crypto/curve25519"
+	"golang.org/x/crypto/curve25519"
 )
 
 func TestSealOpen(t *testing.T) {

nacl/secretbox/secretbox.go

@@ -18,8 +18,8 @@ This package is interoperable with NaCl: http://nacl.cr.yp.to/secretbox.html.
 package secretbox
 
 import (
-	"code.google.com/p/go.crypto/poly1305"
-	"code.google.com/p/go.crypto/salsa20/salsa"
+	"golang.org/x/crypto/poly1305"
+	"golang.org/x/crypto/salsa20/salsa"
 )
 
 // Overhead is the number of bytes of overhead when boxing a message.