Debugger: Don't show a location marker in the mixed master engine

Task-number: QTCREATORBUG-14087
Change-Id: I7e8f116c97cdea0bd8234d060d068435229e6fc2
Reviewed-by: Christian Stenger <christian.stenger@theqtcompany.com>

src/plugins/debugger/cdb/cdbengine.h

@@ -79,6 +79,9 @@ public:
 
     virtual bool setToolTipExpression(TextEditor::TextEditorWidget *editorWidget,
                                       const DebuggerToolTipContext &context);
+
+    virtual DebuggerEngine *cppEngine() { return this; }
+
     virtual void setupEngine();
     virtual void setupInferior();
     virtual void runEngine();