fix[example]: fixed create.vue cache error

https://github.com/PanJiaChen/vue-element-admin/issues/2608

src/views/example/components/ArticleDetail.vue

@@ -170,8 +170,6 @@ export default {
     if (this.isEdit) {
       const id = this.$route.params && this.$route.params.id
       this.fetchData(id)
-    } else {
-      this.postForm = Object.assign({}, defaultForm)
     }
 
     // Why need to make a copy of this.$route here?

src/views/example/create.vue

@@ -6,7 +6,7 @@
 import ArticleDetail from './components/ArticleDetail'
 
 export default {
-  name: 'CreateForm',
+  name: 'CreateArticle',
   components: { ArticleDetail }
 }
 </script>