Valgrind: Code cosmetics

Use covariant return types for aspect creation,
other aspects already did, it does no harm, so follow suit.
Add 'override'. Remove empty line.

Change-Id: I68e85f64e60becf47ee407eb6d1800f43c4d0755
Reviewed-by: Christian Stenger <christian.stenger@theqtcompany.com>

src/plugins/valgrind/valgrindruncontrolfactory.cpp

@@ -124,15 +124,14 @@ public:
         resetProjectToGlobalSettings();
     }
 
-    IRunConfigurationAspect *create(RunConfiguration *parent) const
+    ValgrindRunConfigurationAspect *create(RunConfiguration *parent) const override
     {
         return new ValgrindRunConfigurationAspect(parent);
     }
 
-    RunConfigWidget *createConfigurationWidget()
+    RunConfigWidget *createConfigurationWidget() override
     {
         return new AnalyzerRunConfigWidget(this);
-
     }
 };