Core: Clean up FileIconProvider interface

Change-Id: I98c3c8796cb887f5bb3c5184854562ff36727836
Reviewed-by: Christian Kandeler <christian.kandeler@digia.com>

src/plugins/coreplugin/coreplugin.cpp

@@ -30,7 +30,6 @@
 #include "coreplugin.h"
 #include "designmode.h"
 #include "editmode.h"
-#include "fileiconprovider.h"
 #include "helpmanager.h"
 #include "mainwindow.h"
 #include "mimedatabase.h"
@@ -67,9 +66,6 @@ CorePlugin::~CorePlugin()
         delete m_designMode;
     }
 
-    // delete FileIconProvider singleton
-    delete FileIconProvider::instance();
-
     delete m_mainWindow;
 }