Editors: Remove useless parent widget argument from create/duplicate

It was never called with a sensible value anyhow, and only complicates things.

Change-Id: I005848700b6c00114d91495670d4a0e15a2d2e64
Reviewed-by: Eike Ziller <eike.ziller@digia.com>

src/plugins/pythoneditor/pythoneditor.h

@@ -46,7 +46,7 @@ public:
     virtual ~PythonEditor();
 
     bool duplicateSupported() const { return true; }
-    Core::IEditor *duplicate(QWidget *parent);
+    Core::IEditor *duplicate();
 
     Core::Id id() const;