Use specific callable_traits includes

In line with the coding standard, use the most specific boost includes
we can, in this case for callable_traits, we only need two structs, not
the whole library.

Change-Id: I0500e5f726b7dc1646fa3fecc47cac5189218c64
Signed-off-by: Ed Tanous <etanous@nvidia.com>
diff --git a/include/sdbusplus/asio/connection.hpp b/include/sdbusplus/asio/connection.hpp
index 1ece736..e33769c 100644
--- a/include/sdbusplus/asio/connection.hpp
+++ b/include/sdbusplus/asio/connection.hpp
@@ -30,7 +30,7 @@
 #ifndef SDBUSPLUS_DISABLE_BOOST_COROUTINES
 #include <boost/asio/spawn.hpp>
 #endif
-#include <boost/callable_traits.hpp>
+#include <boost/callable_traits/args.hpp>
 #include <sdbusplus/asio/detail/async_send_handler.hpp>
 #include <sdbusplus/message.hpp>
 #include <sdbusplus/utility/read_into_tuple.hpp>
diff --git a/include/sdbusplus/asio/object_server.hpp b/include/sdbusplus/asio/object_server.hpp
index f00b545..94f8f33 100644
--- a/include/sdbusplus/asio/object_server.hpp
+++ b/include/sdbusplus/asio/object_server.hpp
@@ -6,6 +6,8 @@
 #define BOOST_COROUTINES_NO_DEPRECATION_WARNING
 #endif
 
+#include <boost/callable_traits/args.hpp>
+#include <boost/callable_traits/return_type.hpp>
 #ifndef SDBUSPLUS_DISABLE_BOOST_COROUTINES
 #include <boost/asio/detached.hpp>
 #include <boost/asio/spawn.hpp>