windowscodecs: Fix interlaced PNG writing.

[Sebastian Lackner]

Am 20.06.2014 22:15, schrieb Vincent Povirk:
> +        row_pointers = HeapAlloc(GetProcessHeap(), 0, This->height * sizeof(png_byte*));
> +        if (!row_pointers)
> +        {
> +            LeaveCriticalSection(&This->lock);
> +            return E_OUTOFMEMORY;
> +        }

There should be a corresponding HeapFree( ... ) to release row_pointers
again.