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

Change-Id: I14b39033b24fd43d85e3f3cb83ac38ea57a4884a
Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
diff --git a/utils.cpp b/utils.cpp
index 124f28f..38e1290 100644
--- a/utils.cpp
+++ b/utils.cpp
@@ -33,7 +33,7 @@
 constexpr auto MAPPER_INTERFACE = "xyz.openbmc_project.ObjectMapper";
 constexpr auto PROPERTY_INTERFACE = "org.freedesktop.DBus.Properties";
 
-void subscribeToSystemdSignals(sdbusplus::bus::bus& bus)
+void subscribeToSystemdSignals(sdbusplus::bus_t& bus)
 {
     auto method = bus.new_method_call(SYSTEMD_SERVICE, SYSTEMD_OBJ_PATH,
                                       SYSTEMD_INTERFACE, "Subscribe");
@@ -55,7 +55,7 @@
     return;
 }
 
-std::string getService(sdbusplus::bus::bus& bus, std::string path,
+std::string getService(sdbusplus::bus_t& bus, std::string path,
                        std::string interface)
 {
     auto mapper = bus.new_method_call(MAPPER_BUSNAME, MAPPER_PATH,