QmlDesigner: Remove visibilityChanged

Change-Id: Ica52f8a9837eb1b041c890181beda839f3b99a4f
Reviewed-by: Tim Jenssen <tim.jenssen@digia.com>

src/plugins/qmldesigner/components/itemlibrary/itemlibrarymodel.cpp

@@ -258,9 +258,6 @@ void ItemLibraryModel::updateVisibility()
 
         changed |= itemLibrarySection->setVisible(sectionVisibility);
     }
-
-    if (changed)
-        emit visibilityChanged();
 }
 
 void ItemLibraryModel::addRoleNames()

src/plugins/qmldesigner/components/itemlibrary/itemlibrarymodel.h

@@ -81,7 +81,6 @@ public slots:
 signals:
     void qmlModelChanged();
     void searchTextChanged();
-    void visibilityChanged();
 
 private: // functions
     void updateVisibility();