QmlProfiler: Don't delete QObjects from outside their home thread

We cannot do this because the parent object needs to be notified.

Change-Id: Id70de2acea4aa241ea0e85b5b02327e1f91b7e68
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/qmlprofiler/qmlprofilermodelmanager.cpp

@@ -344,7 +344,7 @@ void QmlProfilerModelManager::save(const QString &filename)
             writer->saveQtd(file);
         else
             writer->saveQzt(file);
-        delete writer;
+        writer->deleteLater();
         file->deleteLater();
     });