gdi32: return non-zero v-refresh value for display devices.

[Henri Verbeet]

On 19 July 2017 at 10:31, Huw Davies <huw at codeweavers.com> wrote:
> The values returned by the testbot range from 1 -- 85, so
> 1 is as good a choice as any.
>
For what it's worth though, I think it shouldn't be much harder to
return the real value from winex11.