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: Ief1b330c4f623ecc1be771f36083780a12260834
diff --git a/test/mock_network_manager.hpp b/test/mock_network_manager.hpp
index dce1b36..741cee9 100644
--- a/test/mock_network_manager.hpp
+++ b/test/mock_network_manager.hpp
@@ -18,7 +18,7 @@
 class MockManager : public phosphor::network::Manager
 {
   public:
-    MockManager(sdbusplus::bus::bus& bus, const char* path,
+    MockManager(sdbusplus::bus_t& bus, const char* path,
                 const std::string& dir) :
         phosphor::network::Manager(bus, path, dir)
     {