Bootstraped value_set type

This whole implementations is buggy:

If the `ws_set_new()` failed, the `free()` call is okay, but not `ws_object_unref()` as the object does not exist.

If the `ws_value_set_init()` call fails, the unref is okay, and the free call.

Maybe I even missed something here. Suggestion: Do not work with jumps in this case.