thermostat: qmqtt: use SIGNAL/SLOT

soft/thermostat/src/mqttclient.cpp

@@ -19,11 +19,11 @@
 MQTTClient::MQTTClient(const QHostAddress& host, const quint16 port,
 			     QObject* parent) : QMQTT::Client(host, port, parent)
 {
-	connect(this, &MQTTClient::connected, this, &MQTTClient::onConnected);
-	connect(this, &MQTTClient::subscribed, this, &MQTTClient::onSubscribed);
-	connect(this, &MQTTClient::received, this, &MQTTClient::onReceived);
-	connect(this, &MQTTClient::published, this, &MQTTClient::onPublished);
-	connect(this, &MQTTClient::error, this, &MQTTClient::onError);
+	connect(this, SIGNAL(connected(void)), this, SLOT(onConnected(void)));
+	connect(this, SIGNAL(subscribed(const QString&)), this, SLOT(onSubscribed(const QString&)));
+	connect(this, SIGNAL(received(const QMQTT::Message&)), this, SLOT(onReceived(const QMQTT::Message&)));
+	connect(this, SIGNAL(published(const QMQTT::Message&, quint16)), this, SLOT(onPublished(const QMQTT::Message&, quint16)));
+	connect(this, SIGNAL(error(const QMQTT::ClientError)), this, SLOT(onError(const QMQTT::ClientError)));
 
 	/*
 	 * 2 more signals: