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_cert_entry.hpp b/bmc-vmi-ca/ca_cert_entry.hpp
index a461632..78f13e8 100644
--- a/bmc-vmi-ca/ca_cert_entry.hpp
+++ b/bmc-vmi-ca/ca_cert_entry.hpp
@@ -45,9 +45,8 @@
      *  @param[in] csr     - csr string
      *  @param[in] cert    - client certificate
      */
-    Entry(sdbusplus::bus::bus& bus, const std::string& objPath,
-          uint32_t entryId, std::string& csr, std::string& cert,
-          CACertMgr& manager) :
+    Entry(sdbusplus::bus_t& bus, const std::string& objPath, uint32_t entryId,
+          std::string& csr, std::string& cert, CACertMgr& manager) :
         internal::EntryInterface(bus, objPath.c_str(),
                                  internal::EntryInterface::action::defer_emit),
         bus(bus), id(entryId), manager(manager)
@@ -64,7 +63,7 @@
 
   protected:
     /** @brief sdbusplus handler */
-    sdbusplus::bus::bus& bus;
+    sdbusplus::bus_t& bus;
     uint32_t id;
     /** @brief object path */
     std::string objectPath;