ddraw: Check for the Palette before using it

[Henri Verbeet]

2011/2/28 André Hentschel <nerv at dawncrow.de>:
>         *Pal = wined3d_palette_get_parent(wined3d_palette);
> -        IDirectDrawPalette_AddRef(*Pal);
> +        if (*Pal) IDirectDrawPalette_AddRef(*Pal);
> +        else hr = DDERR_NOPALETTEATTACHED;
This doesn't make sense, the parent shouldn't be NULL. You should
figure out what sets it to NULL. You also may want to try warn+heap to
see if it's getting free'd or corrupted somewhere.