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: I29672cb229bd07022b00f52105ac1d50ecacca62
diff --git a/ext_interface.cpp b/ext_interface.cpp
index 8e6db17..cc3475e 100644
--- a/ext_interface.cpp
+++ b/ext_interface.cpp
@@ -28,7 +28,7 @@
  *
  * @return distinct dbus name for input interface/path
  **/
-std::string getService(sdbusplus::bus::bus& bus, const std::string& intf,
+std::string getService(sdbusplus::bus_t& bus, const std::string& intf,
                        const std::string& path)
 {