frozen with force_default_on_freeze can change owner

tiramisu/value.py

@@ -382,7 +382,7 @@ class Values(object):
         self._setowner(opt, path, owner)
 
     def _setowner(self, opt, path, owner):
-        if self._getowner(opt, path) == owners.default:  # pragma: optional cover
+        if not self._p_.hasvalue(path):  # pragma: optional cover
             raise ConfigError(_('no value for {0} cannot change owner to {1}'
                                 '').format(path, owner))
         self._getcontext().cfgimpl_get_settings().validate_properties(opt,