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: I5d9984f2642be11be6255f8adbf4586dd8f05a40
Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
diff --git a/src/system.cpp b/src/system.cpp
index e4ea038..c5c905e 100644
--- a/src/system.cpp
+++ b/src/system.cpp
@@ -69,7 +69,7 @@
         "00000000-0000-0000-0000-000000000000");
 }
 
-static std::string getService(sdbusplus::bus::bus& bus,
+static std::string getService(sdbusplus::bus_t& bus,
                               const std::string& objectPath,
                               const std::string& interface)
 {
@@ -101,7 +101,7 @@
     return response[0].first;
 }
 
-static void setProperty(sdbusplus::bus::bus& bus, const std::string& objectPath,
+static void setProperty(sdbusplus::bus_t& bus, const std::string& objectPath,
                         const std::string& interface,
                         const std::string& propertyName,
                         const std::string& value)