ddraw: Fix refcounting of palettes

[Cihan Altinay]

Stefan Dösinger wrote:
> Am Sonntag, 16. März 2008 14:44:37 schrieb bobbyg at gmx.net:
> I think it would be better to set pal = NULL if there is no wined3d palette 
> returned a few lines above the place you're changing.

That's fine with me but it would mean setting it to NULL in every
iteration instead of only when necessary.

>> While tracing this bug I noticed that
>> IWineD3DBaseSurfaceImpl_GetPalette() does not call AddRef when
>> returning the palette. Is that intentional?
> This looks like it needs a fix

Ok, I'll add that to the same patch since the problem is related.

Cheers,
Cihan