go.crypto: add exp/terminal as code.google.com/p/go.crypto/ssh/terminal.

This removes the sole "exp/foo" import in the Go subrepos.
A separate CL will remove exp/terminal from the standard Go repository.

R=golang-dev, dave, r
CC=golang-dev
https://golang.org/cl/5966045

ssh/example_test.go

@@ -6,9 +6,10 @@ package ssh
 
 import (
 	"bytes"
-	"exp/terminal"
 	"fmt"
 	"io/ioutil"
+
+	"code.google.com/p/go.crypto/ssh/terminal"
 )
 
 func ExampleListen() {