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: Id8497e7fed0c6a278e29528d07486f5159687696
diff --git a/presence/gpio_presence.cpp b/presence/gpio_presence.cpp
index 765ca55..e473fea 100644
--- a/presence/gpio_presence.cpp
+++ b/presence/gpio_presence.cpp
@@ -28,7 +28,7 @@
 constexpr auto MAPPER_INTERFACE = "xyz.openbmc_project.ObjectMapper";
 
 std::string getService(const std::string& path, const std::string& interface,
-                       sdbusplus::bus::bus& bus)
+                       sdbusplus::bus_t& bus)
 {
     auto mapperCall = bus.new_method_call(MAPPER_BUSNAME, MAPPER_PATH,
                                           MAPPER_INTERFACE, "GetObject");
diff --git a/presence/gpio_presence.hpp b/presence/gpio_presence.hpp
index ec26fde..4b9b24c 100644
--- a/presence/gpio_presence.hpp
+++ b/presence/gpio_presence.hpp
@@ -5,6 +5,7 @@
 
 #include <cstdlib>
 #include <experimental/filesystem>
+#include <sdbusplus/bus.hpp>
 #include <string>
 
 namespace phosphor
@@ -64,7 +65,7 @@
      *  @param[in] handler   - IO callback handler. Defaults to one in this
      *                        class
      */
-    Presence(sdbusplus::bus::bus& bus, const std::string& inventory,
+    Presence(sdbusplus::bus_t& bus, const std::string& inventory,
              const std::string& path, const unsigned int key,
              const std::string& name, EventPtr& event,
              const std::vector<Driver>& drivers,
@@ -117,7 +118,7 @@
     ObjectMap getObjectMap(bool present);
 
     /** @brief Connection for sdbusplus bus */
-    sdbusplus::bus::bus& bus;
+    sdbusplus::bus_t& bus;
 
     /**
      * @brief Read the GPIO device to determine initial presence and set
@@ -171,7 +172,7 @@
  * @return The service name
  */
 std::string getService(const std::string& path, const std::string& interface,
-                       sdbusplus::bus::bus& bus);
+                       sdbusplus::bus_t& bus);
 
 } // namespace presence
 } // namespace gpio