tiramisu/values: _empty should not validate with defaultvalue, defaultvalue is already in value

tiramisu/value.py

@@ -66,8 +66,6 @@ class Values(object):
            (opt.optimpl_is_multi() and (value == [] or
                                         None in value or empty in value)):
             return True
-        if self.is_default_owner(opt) and opt.optimpl_is_empty_by_default():
-            return True
         return False
 
     def _getcallback_value(self, opt):