Fix typo in TexAtlas.PackAtlas

This has been here since it was added in a2ba761ae. I think it's never caused
problems because the two lists are the same in all cases where the method's
result is used (the single caller, ArtManager.Close, immediately checks the
result of this method and throws if multiple atlases are used).

src/BizHawk.Bizware.BizwareGL/TexAtlas.cs

@@ -135,7 +135,7 @@ namespace BizHawk.Bizware.BizwareGL
 			var atlas = ret.Atlases[ret.Atlases.Count - 1];
 			atlas.Size.Width = tfpFinal.w;
 			atlas.Size.Height = tfpFinal.h;
-			atlas.Items = new List<RectItem>(items);
+			atlas.Items = new List<RectItem>(currentItems);
 			foreach (var item in currentItems)
 			{
 				object o = item.Item;