Stop processing response when record is not valid

issue8571 introduced the validate attribute but the test against validate
record is wrong as it stop processing when the record is actually valid.

issue8886
review252731002

src/wizard.js

@@ -130,7 +130,7 @@
         response: function(definition) {
             this.__waiting_response = false;
             this.screen.current_view.set_value();
-            if (definition.validate && this.screen.current_record.validate(
+            if (definition.validate && !this.screen.current_record.validate(
                     null, null, null, true)) {
                 this.screen.display(true);
                 this.info_bar.message(