Move include errorno & limits from hash.hpp into hash_float where they should be.

[SVN r32777]

include/boost/functional/detail/hash_float.hpp

@@ -16,6 +16,8 @@
 #endif
 
 #include <boost/functional/detail/float_functions.hpp>
+#include <errno.h>
+#include <boost/limits.hpp>
 
 namespace boost
 {

include/boost/functional/hash/hash.hpp

@@ -17,8 +17,6 @@
 
 #include <boost/functional/hash_fwd.hpp>
 #include <functional>
-#include <errno.h>
-#include <boost/limits.hpp>
 #include <boost/functional/detail/hash_float.hpp>
 #include <boost/functional/detail/container_fwd.hpp>