Revert "ssh: add support for banners"

This reverts commit ed5229da99.

Reason for revert: missing language tag in banner message breaks auth against other implementations.

Change-Id: I18ac5b3fe3b4693688b82ff4b0db02dab739c45b
Reviewed-on: https://go-review.googlesource.com/72381
Reviewed-by: Han-Wen Nienhuys <hanwen@google.com>
Run-TryBot: Han-Wen Nienhuys <hanwen@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

ssh/client.go

@@ -9,7 +9,6 @@ import (
 	"errors"
 	"fmt"
 	"net"
-	"os"
 	"sync"
 	"time"
 )
@@ -188,10 +187,6 @@ func Dial(network, addr string, config *ClientConfig) (*Client, error) {
 // net.Conn underlying the the SSH connection.
 type HostKeyCallback func(hostname string, remote net.Addr, key PublicKey) error
 
-// BannerCallback is the function type used for treat the banner sent by
-// the server. A BannerCallback receives the message sent by the remote server.
-type BannerCallback func(message string) error
-
 // A ClientConfig structure is used to configure a Client. It must not be
 // modified after having been passed to an SSH function.
 type ClientConfig struct {
@@ -214,12 +209,6 @@ type ClientConfig struct {
 	// FixedHostKey can be used for simplistic host key checks.
 	HostKeyCallback HostKeyCallback
 
-	// BannerCallback is called during the SSH dance to display a custom
-	// server's message. The client configuration can supply this callback to
-	// handle it as wished. The function BannerDisplayStderr can be used for
-	// simplistic display on Stderr.
-	BannerCallback BannerCallback
-
 	// ClientVersion contains the version identification string that will
 	// be used for the connection. If empty, a reasonable default is used.
 	ClientVersion string
@@ -266,13 +255,3 @@ func FixedHostKey(key PublicKey) HostKeyCallback {
 	hk := &fixedHostKey{key}
 	return hk.check
 }
-
-// BannerDisplayStderr returns a function that can be used for
-// ClientConfig.BannerCallback to display banners on os.Stderr.
-func BannerDisplayStderr() BannerCallback {
-	return func(banner string) error {
-		_, err := os.Stderr.WriteString(banner)
-
-		return err
-	}
-}