simple-damage: fix rotating-transform option
Previously !51 (closed), rebased and different branch.
If --rotating-transform is set, the damage calculation of the previous position of the ball has to be done with the old transform value, not the already updated one.
Note: this is still broken when using in combination with surface damage and viewport, as it's a rather complicated scenario and surface-damage is kinda legacy anyways.
This helps a lot on weston but there seem to be some some issues left in the compositor. On mutter it renders perfectly, with or without --use-damage-buffer.
Helps with: #155
Context: !41 (closed) (comment 54445)