message: fix if no el was provided when caching scopes
diff: @@ -627,7 +627,9 @@ export default class Validator {
  field.events = {};
  this._assignFlags(field);
  // cache the scope property.
  + if (field.el && isCallable(field.el.setAttribute)) {
  field.el.setAttribute('data-vv-scope', field.scope);
  + }
  if (field.listeners.classes) {
  field.listeners.classes.attach(field);
  