nodetypes: attrDefaults - use MNodeClass in 2012, _GhostObjMaker otherwise
nodetypes: attrDefaults - use MNodeClass in 2012, _GhostObjMaker otherwise

david-lassonde-adsk/pymel,assumptionsoup/pymel,david-lassonde-adsk/pymel,shrtcww/pymel,juggernate/pymel,AtonLerin/pymel,assumptionsoup/pymel,leonsooi/pymel,AtonLerin/pymel,shrtcww/pymel,juggernate/pymel,leonsooi/pymel