IEditor: Make duplicatesSupported a value member

Change-Id: Iee75dd4155d5074bb319df79d006b6d5e2989e14
Reviewed-by: Eike Ziller <eike.ziller@digia.com>

src/plugins/qmakeprojectmanager/profileeditor.cpp

@@ -57,6 +57,7 @@ ProFileEditor::ProFileEditor(ProFileEditorWidget *editor)
 {
     setContext(Core::Context(Constants::C_PROFILEEDITOR,
               TextEditor::Constants::C_TEXTEDITOR));
+    setDuplicateSupported(true);
 }
 
 Core::IEditor *ProFileEditor::duplicate()