sdbusplus: use shorter type aliases

The sdbusplus headers provide shortened aliases for many types.
Switch to using them to provide better code clarity and shorter
lines.  Possible replacements are for:
  * bus_t
  * exception_t
  * manager_t
  * match_t
  * message_t
  * object_t
  * slot_t

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I9f166640fbf9d4ee3fb24b542a73237cdf54f775
diff --git a/attn/attn_dbus.hpp b/attn/attn_dbus.hpp
index b01c82d..6c2d608 100644
--- a/attn/attn_dbus.hpp
+++ b/attn/attn_dbus.hpp
@@ -22,8 +22,7 @@
  *
  **/
 int dbusMethod(const std::string& i_path, const std::string& i_interface,
-               const std::string& i_function,
-               sdbusplus::message::message& o_method);
+               const std::string& i_function, sdbusplus::message_t& o_method);
 
 /**
  * Create a PEL from raw PEL data