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: Ic0fe1ed7e19cf114b8666d49d4d670c7d9ec595d
diff --git a/utility.cpp b/utility.cpp
index 836bd33..bcfc35e 100644
--- a/utility.cpp
+++ b/utility.cpp
@@ -29,7 +29,7 @@
 using namespace phosphor::logging;
 
 std::string getService(const std::string& path, const std::string& interface,
-                       sdbusplus::bus::bus& bus)
+                       sdbusplus::bus_t& bus)
 {
     auto method = bus.new_method_call(MAPPER_BUSNAME, MAPPER_PATH,
                                       MAPPER_INTERFACE, "GetObject");