term/winconsole: Identify tty correctly, fix resize problem

This change fixes a bug where stdout/stderr handles are not identified
correctly.

Previously we used to set the window size to fixed size to fit the default
tty size on the host (80x24). Now the attach/exec commands can correctly
get the terminal size from windows.

We still do not `monitorTtySize()` correctly on windows and update the tty
size on the host-side, in order to fix that we'll provide a
platform-specific `monitorTtySize` implementation in the future.

Signed-off-by: Ahmet Alp Balkan <ahmetalpbalkan@gmail.com>
(cherry picked from commit 0532dcf3dc)

Docker-DCO-1.1-Signed-off-by: Jessie Frazelle <hugs@docker.com> (github: jfrazelle)

pkg/term/winconsole/console_windows.go

@@ -241,8 +241,6 @@ func StdStreams() (stdIn io.ReadCloser, stdOut io.Writer, stdErr io.Writer) {
 		}
 		handler.screenBufferInfo = screenBufferInfo
 
-		// Set the window size
-		SetWindowSize(stdoutHandle, DEFAULT_WIDTH, DEFAULT_HEIGHT, DEFAULT_HEIGHT)
 		buffer = make([]CHAR_INFO, screenBufferInfo.MaximumWindowSize.X*screenBufferInfo.MaximumWindowSize.Y)
 
 		stdOut = &terminalWriter{
@@ -283,6 +281,12 @@ func GetHandleInfo(in interface{}) (uintptr, bool) {
 			isTerminalIn = IsTerminal(inFd)
 		}
 	}
+	if tr, ok := in.(*terminalWriter); ok {
+		if file, ok := tr.wrappedWriter.(*os.File); ok {
+			inFd = file.Fd()
+			isTerminalIn = IsTerminal(inFd)
+		}
+	}
 	return inFd, isTerminalIn
 }