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/cmakeprojectmanager/cmakerunconfiguration.h

@@ -91,6 +91,7 @@ public:
     void setEnabled(bool b);
 
     bool isEnabled() const;
+    QString disabledReason() const;
 
 signals:
     void baseEnvironmentChanged();