Add RunConfiguration::disabledReason

Not used yet

Change-Id: I76b3b81282dea4bca97eaf64e297154a20cf2096
Reviewed-on: http://codereview.qt.nokia.com/190
Reviewed-by: Christian Kandeler <christian.kandeler@nokia.com>

src/plugins/qmlprojectmanager/qmlprojectrunconfiguration.h

@@ -98,6 +98,7 @@ public:
 
     // RunConfiguration
     bool isEnabled() const;
+    QString disabledReason() const;
     virtual QWidget *createConfigurationWidget();
     Utils::OutputFormatter *createOutputFormatter() const;
     QVariantMap toMap() const;