UPDATE_STATE_IF_NECESSARY: Un-macroize this.  Renamed to function
unghostify() and changed (slightly) the return semantics.

ghostify(): Don't use the NON_GHOST_COUNT macro.  Add some comments.

Per_setstate(), Per__getstate__(), Per_getattr(), _setattro(): Use
unghostify() instead of UPDATE_STATE_IF_NECESSARY.