QmlProfiler: Add another data state "ClearingData"

This allows us to steer the timeline models in a more fine grained
way and avoid duplicate processing of the same data. We don't need
to rebuild everything on stateChanged of the model manager then.

Task-number: QTCREATORBUG-10950
Change-Id: I2aa9a96a33c602f062fc3b644ac06280ba7cd45a
Reviewed-by: Kai Koehne <kai.koehne@digia.com>

src/plugins/qmlprofiler/qmlprofilermodelmanager.h

@@ -52,6 +52,7 @@ public:
         Empty,
         AcquiringData,
         ProcessingData,
+        ClearingData,
         Done
     };