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: Ie530f2c63000bbfac7c5fbbc74ebe6bc8c07fb1a
diff --git a/test/test_activation.cpp b/test/test_activation.cpp
index 8da5b2d..2e93672 100644
--- a/test/test_activation.cpp
+++ b/test/test_activation.cpp
@@ -60,7 +60,7 @@
     }
 
     sdbusplus::SdBusMock sdbusMock;
-    sdbusplus::bus::bus mockedBus = sdbusplus::get_mocked_new(&sdbusMock);
+    sdbusplus::bus_t mockedBus = sdbusplus::get_mocked_new(&sdbusMock);
     const utils::MockedUtils& mockedUtils;
     MockedAssociationInterface mockedAssociationInterface;
     MockedActivationListener mockedActivationListener;