ProjectExplorer: Sprinkle overrides over the code

Sprinkle overrides over code derived from classes in ProjectExplorer

Change-Id: Ia4cc25649f7dc00b0ea126d8176a59afbc5ed574
Reviewed-by: hjk <hjk@theqtcompany.com>

src/plugins/clangstaticanalyzer/clangstaticanalyzerruncontrol.h

@@ -57,8 +57,8 @@ public:
                                   Core::Id runMode,
                                   const CppTools::ProjectInfo &projectInfo);
 
-    bool startEngine();
-    void stopEngine();
+    bool startEngine() override;
+    void stopEngine() override;
 
     bool success() const { return m_success; } // For testing.