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/image_manager_main.cpp b/image_manager_main.cpp
index f4dc03f..961f245 100644
--- a/image_manager_main.cpp
+++ b/image_manager_main.cpp
@@ -17,7 +17,7 @@
     sd_event* loop = nullptr;
     sd_event_default(&loop);
 
-    sdbusplus::server::manager::manager objManager(bus, SOFTWARE_OBJPATH);
+    sdbusplus::server::manager_t objManager(bus, SOFTWARE_OBJPATH);
     bus.request_name(VERSION_BUSNAME);
 
     try