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/test_network_manager.cpp b/test/test_network_manager.cpp
index 76983ed..4e81d48 100644
--- a/test/test_network_manager.cpp
+++ b/test/test_network_manager.cpp
@@ -24,7 +24,7 @@
 class TestNetworkManager : public stdplus::gtest::TestWithTmp
 {
   public:
-    sdbusplus::bus::bus bus;
+    sdbusplus::bus_t bus;
     MockManager manager;
     TestNetworkManager() :
         bus(sdbusplus::bus::new_default()),