Unordered: Merge to release. Fixes #6522.

Fixes undefined macros, removes some unused code and fix some potential issues
for when `std::allocator_traits` is used.


[SVN r76943]

test/unordered/compile_tests.hpp

@@ -22,6 +22,7 @@
 #include <boost/type_traits/is_convertible.hpp>
 #include <boost/iterator/iterator_traits.hpp>
 #include <boost/limits.hpp>
+#include <boost/utility/swap.hpp>
 #include "../helpers/check_return_type.hpp"
 
 typedef long double comparison_type;