Stop using BOOST_DEDUCED_TYPENAME

We no longer support any of the compilers that require it. I'd be very
surprised if anything was working on them.

test/unordered/simple_tests.cpp

@@ -73,7 +73,7 @@ template <class X> void simple_test(X const& a)
   }
 
   {
-    BOOST_TEST(a.size() == static_cast<BOOST_DEDUCED_TYPENAME X::size_type>(
+    BOOST_TEST(a.size() == static_cast<typename X::size_type>(
                              std::distance(a.begin(), a.end())));
   }