Accessibility: unref the object only if it exists.
Accessibility: unref the object only if it exists.

If the type returned by evas_object_type_get is "", no object will be
created. There is no reason why unref would be invoked.
It removes all the bad prints in accessibility tests about obj_id NULL.

@fix

tasn/elementary,rvandegrift/elementary,FlorentRevest/Elementary,tasn/elementary,rvandegrift/elementary,rvandegrift/elementary,FlorentRevest/Elementary,tasn/elementary,tasn/elementary,tasn/elementary,FlorentRevest/Elementary,rvandegrift/elementary,FlorentRevest/Elementary