ssh/terminal: account for win32 api changes

The API changed for this function, since the call always succeeds.
Update this user of it accordingly.

Fixes: golang/go#34461

Change-Id: I9d19b70767fc6b1b9292ad8732dd8e54bb6a8ae0
Reviewed-on: https://go-review.googlesource.com/c/crypto/+/196897
Run-TryBot: Jason A. Donenfeld <Jason@zx2c4.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

util_windows.go

@@ -94,8 +94,7 @@ func ReadPassword(fd int) ([]byte, error) {
 	defer windows.SetConsoleMode(windows.Handle(fd), old)
 
 	var h windows.Handle
-	p, _ := windows.GetCurrentProcess()
-	if err := windows.DuplicateHandle(p, windows.Handle(fd), p, &h, 0, false, windows.DUPLICATE_SAME_ACCESS); err != nil {
+	if err := windows.DuplicateHandle(windows.GetCurrentProcess(), windows.Handle(fd), windows.GetCurrentProcess(), &h, 0, false, windows.DUPLICATE_SAME_ACCESS); err != nil {
 		return nil, err
 	}