Remove tabs in file.

[SVN r24043]

test/concept_tests.cpp

@@ -89,7 +89,7 @@ main()
     boost_concepts::RandomAccessTraversalConcept<old_iterator> >();
 
   boost::function_requires<
-	boost_concepts::InteroperableIteratorConcept<int*, int const*> >();
+    boost_concepts::InteroperableIteratorConcept<int*, int const*> >();
 
   return 0;
 }