change std::out_of_range constractor string (what_arg)

Author: cnagune

boost/network/uri/decode.hpp

@@ -59,9 +59,9 @@ OutputIterator decode(const InputIterator &in_begin,
   OutputIterator out = out_begin;
   while (it != in_end) {
     if (*it == '%') {
-	  if (++it == in_end) throw std::out_of_range("out_of_range exception");
+	  if (++it == in_end) throw std::out_of_range("unexpected end of stream");
       value_type v0 = detail::letter_to_hex(*it);
-	  if (++it == in_end) throw std::out_of_range("out_of_range exception");
+	  if (++it == in_end) throw std::out_of_range("unexpected end of stream");
       value_type v1 = detail::letter_to_hex(*it);
       ++it;
       *out++ = 0x10 * v0 + v1;