修改vue-ant-design框架中的form表單校驗在ie瀏覽器中打開后默認校驗，輸入框出現錯誤提示的bug

<a-form-item >

                          <a-input

                            placeholder="用戶名"

                              v-decorator="[

                                'userName',

                                {rules: [{ required: true, message: '請填寫用戶名' }], validateTrigger:'blur'}//設置此屬性設置當輸入框失焦時去校驗

                              ]"

                            />

                      </a-form-item>