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_dump.cpp b/attn/attn_dump.cpp
index c3dc5b2..6a106a0 100644
--- a/attn/attn_dump.cpp
+++ b/attn/attn_dump.cpp
@@ -20,8 +20,7 @@
  * @param[out] o_dumpStatus Dump status dbus response string
  * @return Always non-zero indicating no error, no cascading callbacks
  */
-uint dumpStatusChanged(sdbusplus::message::message& i_msg,
-                       std::string& o_dumpStatus)
+uint dumpStatusChanged(sdbusplus::message_t& i_msg, std::string& o_dumpStatus)
 {
     // reply (msg) will be a property change message
     std::string interface;
@@ -107,7 +106,7 @@
     constexpr auto interface = "xyz.openbmc_project.Dump.Create";
     constexpr auto function  = "CreateDump";
 
-    sdbusplus::message::message method;
+    sdbusplus::message_t method;
 
     if (0 == dbusMethod(path, interface, function, method))
     {