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: I19e094a2a99893627dbb82b615f630b87ad90fdd
diff --git a/test/mock_user_mgr.hpp b/test/mock_user_mgr.hpp
index 70d696c..9a0ecdd 100644
--- a/test/mock_user_mgr.hpp
+++ b/test/mock_user_mgr.hpp
@@ -12,7 +12,7 @@
 class MockManager : public UserMgr
 {
   public:
-    MockManager(sdbusplus::bus::bus& bus, const char* path) : UserMgr(bus, path)
+    MockManager(sdbusplus::bus_t& bus, const char* path) : UserMgr(bus, path)
     {}
 
     MOCK_METHOD1(getLdapGroupName, std::string(const std::string& userName));