Only use Visual C++ pragma for appropriate versions.

[SVN r86671]

include/boost/functional/hash/hash.hpp

@@ -26,11 +26,15 @@
 
 #if defined(BOOST_MSVC)
 #pragma warning(push)
+
+#if BOOST_MSVC >= 1400
 #pragma warning(disable:6295) // Ill-defined for-loop : 'unsigned int' values
                               // are always of range '0' to '4294967295'.
                               // Loop executes infinitely.
 #endif
 
+#endif
+
 namespace boost
 {
     namespace hash_detail