优化mqtt中断连接操作

src/plugins/MMCMQTT/store.js

@@ -90,10 +90,12 @@ export default {
     },
     /**
      * 断开mqtt连接
-     * @param {} param0 
+     * @param {} param0
      */
-    end({ state }){
+    end({ state, commit }) {
       state.client.end();
+      commit('setClient', null);
+      commit("setClientId", '');
     },
     /**
      * 订阅