change docker client sdk version

vendor/github.com/docker/docker/client/container_attach.go

@@ -1,36 +1,16 @@
-package client // import "github.com/docker/docker/client"
+package client
 
 import (
-	"context"
 	"net/url"
 
 	"github.com/docker/docker/api/types"
+	"golang.org/x/net/context"
 )
 
 // ContainerAttach attaches a connection to a container in the server.
 // It returns a types.HijackedConnection with the hijacked connection
 // and the a reader to get output. It's up to the called to close
 // the hijacked connection by calling types.HijackedResponse.Close.
-//
-// The stream format on the response will be in one of two formats:
-//
-// If the container is using a TTY, there is only a single stream (stdout), and
-// data is copied directly from the container output stream, no extra
-// multiplexing or headers.
-//
-// If the container is *not* using a TTY, streams for stdout and stderr are
-// multiplexed.
-// The format of the multiplexed stream is as follows:
-//
-//    [8]byte{STREAM_TYPE, 0, 0, 0, SIZE1, SIZE2, SIZE3, SIZE4}[]byte{OUTPUT}
-//
-// STREAM_TYPE can be 1 for stdout and 2 for stderr
-//
-// SIZE1, SIZE2, SIZE3, and SIZE4 are four bytes of uint32 encoded as big endian.
-// This is the size of OUTPUT.
-//
-// You can use github.com/docker/docker/pkg/stdcopy.StdCopy to demultiplex this
-// stream.
 func (cli *Client) ContainerAttach(ctx context.Context, container string, options types.ContainerAttachOptions) (types.HijackedResponse, error) {
 	query := url.Values{}
 	if options.Stream {