Use new connect syntax for QMetaObject::invokeMethod

src/device/devicedatabasebackend.cpp

@@ -58,7 +58,7 @@ void DeviceDatabaseBackend::Close() {
 }
 
 void DeviceDatabaseBackend::ExitAsync() {
-  QMetaObject::invokeMethod(this, "Exit", Qt::QueuedConnection);
+  QMetaObject::invokeMethod(this, &DeviceDatabaseBackend::Exit, Qt::QueuedConnection);
 }
 
 void DeviceDatabaseBackend::Exit() {

src/device/devicelister.cpp

@@ -87,7 +87,7 @@ void DeviceLister::MountDevice(const QString &id, const int request_id) {
 }
 
 void DeviceLister::ExitAsync() {
-  QMetaObject::invokeMethod(this, "Exit", Qt::QueuedConnection);
+  QMetaObject::invokeMethod(this, &DeviceLister::Exit, Qt::QueuedConnection);
 }
 
 void DeviceLister::Exit() {

src/device/filesystemdevice.cpp

@@ -85,7 +85,7 @@ bool FilesystemDevice::Init() {
 }
 
 void FilesystemDevice::CloseAsync() {
-  QMetaObject::invokeMethod(this, "Close", Qt::QueuedConnection);
+  QMetaObject::invokeMethod(this, &FilesystemDevice::Close, Qt::QueuedConnection);
 }
 
 void FilesystemDevice::Close() {