dxdiag: Do not omit mandatory argument to WriteFile.

[Lauri Kenttä]

On 2014-07-12 20:50, Thomas Faber wrote:
> It can only be NULL for asynchronous writes. Notice the last sentence.
> Invocations with both lpNumberOfBytesWritten = NULL and
> lpOverlapped = NULL always crash on Windows.

Indeed. I accidentally skipped the "not". :)

-- 
Lauri Kenttä