windows: correct GetStdHandle definition

GetStdHandle: https://msdn.microsoft.com/en-us/library/windows/desktop/ms683231(v=vs.85).aspx
DWORD: https://msdn.microsoft.com/en-us/library/windows/desktop/aa383751(v=vs.85).aspx

Change-Id: I2fb794f85418e7846687911c4513886eb1803770
Reviewed-on: https://go-review.googlesource.com/39608
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
3 files changed