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: I96286490697ce5d7fecc1c9c358f5f1d054137ec
diff --git a/item_updater_helper.hpp b/item_updater_helper.hpp
index b328285..81d66d9 100644
--- a/item_updater_helper.hpp
+++ b/item_updater_helper.hpp
@@ -24,7 +24,7 @@
      *
      *  @param[in] bus - sdbusplus D-Bus bus connection
      */
-    explicit Helper(sdbusplus::bus::bus& bus) : bus(bus)
+    explicit Helper(sdbusplus::bus_t& bus) : bus(bus)
     {
         // Empty
     }
@@ -65,7 +65,7 @@
 
   private:
     /** @brief Persistent sdbusplus D-Bus bus connection. */
-    sdbusplus::bus::bus& bus;
+    sdbusplus::bus_t& bus;
 };
 
 } // namespace updater