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.cpp b/attn/attn_dbus.cpp
index 2d11bde..7613777 100644
--- a/attn/attn_dbus.cpp
+++ b/attn/attn_dbus.cpp
@@ -12,8 +12,7 @@
 
 /** @brief Create a dbus method */
 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)
 {
     int rc = RC_DBUS_ERROR; // assume error
 
@@ -77,7 +76,7 @@
     constexpr auto interface = "xyz.openbmc_project.Logging.Create";
     constexpr auto function  = "Create";
 
-    sdbusplus::message::message method;
+    sdbusplus::message_t method;
 
     if (0 == dbusMethod(pathLogging, interface, function, method))
     {
@@ -108,7 +107,7 @@
     constexpr auto interface = "org.open_power.Logging.PEL";
     constexpr auto function  = "GetPEL";
 
-    sdbusplus::message::message method;
+    sdbusplus::message_t method;
 
     if (0 == dbusMethod(pathLogging, interface, function, method))
     {