Blender Git Loki

improved fix for [#24267] Hook fails after Solidify
Rather then have the modifier calculate ORIGINDEX weather its needed or not (incorrect if it wasn't the first modifier on the stack),
create ORIGINDEX layer initially if any of the modifiers use it.
This way hook also works after Mirror and Screw modifiers which have the ORIGINDEX layer copied implicitly with DM_copy_vert_data().

This wasn't possible to check for before because this flag was always enabled so it would be passed to DM_set_only_copy().
Now just add the flag whenever calling DM_set_only_copy().