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: I9029cc722e7712633c15436bd3868d8c3209f567
diff --git a/presence/json_parser.hpp b/presence/json_parser.hpp
index 216c235..7dbe115 100644
--- a/presence/json_parser.hpp
+++ b/presence/json_parser.hpp
@@ -55,7 +55,7 @@
      *
      * @param[in] bus - sdbusplus bus object
      */
-    explicit JsonConfig(sdbusplus::bus::bus& bus);
+    explicit JsonConfig(sdbusplus::bus_t& bus);
 
     /**
      * @brief Get the json config based fan presence policies
@@ -86,7 +86,7 @@
     static policies _policies;
 
     /* The sdbusplus bus object */
-    sdbusplus::bus::bus& _bus;
+    sdbusplus::bus_t& _bus;
 
     /* List of Fan objects to have presence policies */
     std::vector<fanPolicy> _fans;