Utils: Emit TypedAspect::volatileValueChanged when it changes

Change-Id: I9a2cf591955332453e6ff9d99c5e18249510599a
Reviewed-by: Marcus Tillmanns <marcus.tillmanns@qt.io>

src/libs/utils/aspects.h

@@ -268,8 +268,11 @@ public:
 
     void setVolatileValue(const ValueType &value)
     {
+        if (m_buffer == value)
+            return;
         m_buffer = value;
         bufferToGui();
+        emit volatileValueChanged();
     }
 
 protected: