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: Ief05bd757cffb1453e058a719ee4b060861752e7
diff --git a/power-sequencer/pgood_monitor.hpp b/power-sequencer/pgood_monitor.hpp
index bc1ffd5..85c20bf 100644
--- a/power-sequencer/pgood_monitor.hpp
+++ b/power-sequencer/pgood_monitor.hpp
@@ -43,7 +43,7 @@
      * @param[in] t - time to allow PGOOD to come up
      */
     PGOODMonitor(std::unique_ptr<phosphor::power::Device>&& d,
-                 sdbusplus::bus::bus& b, const sdeventplus::Event& e,
+                 sdbusplus::bus_t& b, const sdeventplus::Event& e,
                  std::chrono::milliseconds& t) :
         DeviceMonitor(std::move(d), e, t),
         bus(b)
@@ -97,7 +97,7 @@
     /**
      * The D-Bus object
      */
-    sdbusplus::bus::bus& bus;
+    sdbusplus::bus_t& bus;
 
     /**
      * The match object for the properties changed signal