Only show the infobar once

Change-Id: I274627999649d00efead89222bbdc325e55932b7
Reviewed-on: http://codereview.qt.nokia.com/2281
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@nokia.com>

src/plugins/cmakeprojectmanager/cmakeeditor.h

@@ -65,6 +65,8 @@ public:
 private slots:
     void markAsChanged();
     void build();
+private:
+    bool m_infoBarShown;
 };
 
 class CMakeEditorWidget : public TextEditor::BaseTextEditorWidget