QmlProfiler: Initialize QmlProfilerDetailsRewriter::detailsRewriter

Change-Id: I4891885ff30c88bdca32af062e161758501db6c1
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

src/plugins/qmlprofiler/qmlprofilerdatamodel.cpp

@@ -48,7 +48,7 @@ public:
     int resolveStackTop();
 
     QVector<QmlEventType> eventTypes;
-    Internal::QmlProfilerDetailsRewriter *detailsRewriter;
+    Internal::QmlProfilerDetailsRewriter *detailsRewriter = 0;
 
     Utils::TemporaryFile file;
     QDataStream eventStream;