fix(miio): Add proper shutdown methods to dummycloud and retrywrapper

backend/lib/core/ValetudoRobot.js

@@ -120,9 +120,6 @@ class ValetudoRobot {
     }
 
 
-    /**
-     * @abstract
-     */
     async shutdown() {
 
     }

backend/lib/miio/RetryWrapper.js

@@ -155,6 +155,10 @@ class RetryWrapper {
             return this.sendMessage(method, args, options);
         }
     }
+
+    async shutdown() {
+        await this.miioSocket.shutdown();
+    }
 }
 
 module.exports = RetryWrapper;

backend/lib/robots/MiioValetudoRobot.js

@@ -478,6 +478,11 @@ class MiioValetudoRobot extends ValetudoRobot {
         Logger.info("LocalSecret " + this.localSecret);
     }
 
+    async shutdown() {
+        await super.shutdown();
+        await this.dummyCloud.shutdown();
+        await this.localSocket.shutdown();
+    }
 
     static READ_DEVICE_CONF(path) {
         let deviceConf;