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: I9bb7b9a430d029ddaf2a08ea26acb775b9b2b152
diff --git a/bmc-vmi-ca/mainapp.cpp b/bmc-vmi-ca/mainapp.cpp
index c33a69d..062a60d 100644
--- a/bmc-vmi-ca/mainapp.cpp
+++ b/bmc-vmi-ca/mainapp.cpp
@@ -11,7 +11,7 @@
     static constexpr auto objPath = "/xyz/openbmc_project/certs/ca";
 
     // Add sdbusplus ObjectManager
-    sdbusplus::server::manager::manager objManager(bus, objPath);
+    sdbusplus::server::manager_t objManager(bus, objPath);
 
     // Get default event loop
     auto event = sdeventplus::Event::get_default();