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: I6a559082fed34ae62b648345ead793436d2d03f6
diff --git a/src/pathwatchimpl.hpp b/src/pathwatchimpl.hpp
index e1e8f97..282ed60 100644
--- a/src/pathwatchimpl.hpp
+++ b/src/pathwatchimpl.hpp
@@ -47,7 +47,7 @@
 
 template <typename DBusInterfaceType>
 void PathWatch<DBusInterfaceType>::callback(Context ctx,
-                                            sdbusplus::message::message& msg)
+                                            sdbusplus::message_t& msg)
 {
     (this->cb)(ctx, msg);
 }