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: I9bb7b9a430d029ddaf2a08ea26acb775b9b2b152
diff --git a/bmc-vmi-ca/ca_certs_manager.hpp b/bmc-vmi-ca/ca_certs_manager.hpp
index 951c0cf..f99a750 100644
--- a/bmc-vmi-ca/ca_certs_manager.hpp
+++ b/bmc-vmi-ca/ca_certs_manager.hpp
@@ -38,7 +38,7 @@
      *  @param[in] bus - Bus to attach to.
      *  @param[in] path - Path to attach at.
      */
-    CACertMgr(sdbusplus::bus::bus& bus, const char* path) :
+    CACertMgr(sdbusplus::bus_t& bus, const char* path) :
         internal::ManagerInterface(bus, path), bus(bus), objectPath(path),
         lastEntryId(0){};
 
@@ -64,7 +64,7 @@
 
   private:
     /** @brief sdbusplus DBus bus connection. */
-    sdbusplus::bus::bus& bus;
+    sdbusplus::bus_t& bus;
     /** @brief object path */
     std::string objectPath;
     /** @brief Id of the last certificate entry */