Adapt include guard to path

dune/fufem/dunepython.hh

 // -*- tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 // vi: set ts=8 sw=4 et sts=4:
-#ifndef DUNE_PYTHON_HH
-#define DUNE_PYTHON_HH
+#ifndef DUNE_FUFEM_PYTHON_HH
+#define DUNE_FUFEM_PYTHON_HH
 
 // Only introduce the dune-python interface if python
 // was found and enabled.