fix old comment

[[Imported from SVN: r5544]]

common/array.hh

 // -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 // vi: set et ts=4 sw=2 sts=2:
-#ifndef DUNE_FIXEDARRAY_HH
-#define DUNE_FIXEDARRAY_HH
+#ifndef DUNE_ARRAY_HH
+#define DUNE_ARRAY_HH
 
 /** \file
     \brief implementation of the stl array class (a static array)
-    and its deprecated ancestor FixedArray
  */
 
 #include <iostream>
@@ -34,7 +33,8 @@ namespace Dune
   using std::tr1::array;
 #else
 
-  /** \brief Simple fixed size array class
+  /** \brief Simple fixed size array class.  This replaces std::array,
+   * if that is not available.
    *
    */
   template<class T, int N>