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: I662faee19b7b289bc0a39665fc5ce9e19406f933
diff --git a/settings_main.cpp b/settings_main.cpp
index 0790a7b..78a0ebe 100644
--- a/settings_main.cpp
+++ b/settings_main.cpp
@@ -12,7 +12,7 @@
     // Add sdbusplus ObjectManager. The settings objects are spread across
     // the object namespace and are not under a (settings) root. Hence register
     // "/" as the path.
-    sdbusplus::server::manager::manager objManager(bus, "/");
+    sdbusplus::server::manager_t objManager(bus, "/");
     bus.request_name(SETTINGS_BUSNAME);
 
     phosphor::settings::Manager mgr(bus);