Network: Use the new invokeMethod overload

Saves us from having to create a lambda functor object.

Change-Id: I5e790e693b57ae414ac6d6be84f18b76b3e8185c
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>

src/network/access/qnetworkreplyfileimpl.cpp

@@ -60,7 +60,7 @@ QNetworkReplyFileImpl::QNetworkReplyFileImpl(QNetworkAccessManager *manager, con
         setFinished(true); // We're finished, will emit finished() after ctor is done.
         QMetaObject::invokeMethod(this, "errorOccurred", Qt::QueuedConnection,
             Q_ARG(QNetworkReply::NetworkError, QNetworkReply::ProtocolInvalidOperationError));
-        QMetaObject::invokeMethod(this, [this](){ fileOpenFinished(false); }, Qt::QueuedConnection);
+        QMetaObject::invokeMethod(this, &QNetworkReplyFileImpl::fileOpenFinished, Qt::QueuedConnection, false);
         return;
     }
 #endif