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: I91502c85799b7d3be22b7d05659ff26bea08c32b
diff --git a/inc/button_interface.hpp b/inc/button_interface.hpp
index 9d85e8e..f05beb9 100644
--- a/inc/button_interface.hpp
+++ b/inc/button_interface.hpp
@@ -10,8 +10,7 @@
 class ButtonIface
 {
   public:
-    ButtonIface(sdbusplus::bus::bus& bus, EventPtr& event,
-                buttonConfig& buttonCfg,
+    ButtonIface(sdbusplus::bus_t& bus, EventPtr& event, buttonConfig& buttonCfg,
                 sd_event_io_handler_t handler = ButtonIface::EventHandler) :
         bus(bus),
         event(event), config(buttonCfg), callbackHandler(handler)
@@ -108,7 +107,7 @@
         }
     }
 
-    sdbusplus::bus::bus& bus;
+    sdbusplus::bus_t& bus;
     EventPtr& event;
     buttonConfig config;
     sd_event_io_handler_t callbackHandler;