use Core::Id for IEditorFactory::id

Change-Id: Iefd67a0461d9016b8ba0f3371df7ec6d42e188c5
Reviewed-on: http://codereview.qt-project.org/4321
Reviewed-by: hjk <qthjk@ovi.com>

src/plugins/vcsbase/basevcseditorfactory.h

@@ -54,7 +54,7 @@ public:
     virtual QStringList mimeTypes() const;
     // IEditorFactory
 
-    virtual QString id() const;
+    virtual Core::Id id() const;
     virtual QString displayName() const;
 
     virtual Core::IFile *open(const QString &fileName);