Fix for "Iterator rbegin()" in densevector, probably copy&paste bug.

[[Imported from SVN: r6608]]

dune/common/densevector.hh

@@ -303,7 +303,7 @@ namespace Dune {
     //! instead.
     Iterator rbegin() DUNE_DEPRECATED_MSG("Use the new method beforeEnd instead")
     {
-      return beforeBegin();
+      return beforeEnd();
     }
 
     //! @returns an iterator that is positioned before