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/certificate.cpp b/certificate.cpp
index f5e8ae9..5ebb4f7 100644
--- a/certificate.cpp
+++ b/certificate.cpp
@@ -228,7 +228,7 @@
     }
 }
 
-Certificate::Certificate(sdbusplus::bus::bus& bus, const std::string& objPath,
+Certificate::Certificate(sdbusplus::bus_t& bus, const std::string& objPath,
                          CertificateType type, const std::string& installPath,
                          const std::string& uploadPath, Watch* watch,
                          Manager& parent) :
@@ -266,7 +266,7 @@
     this->emit_object_added();
 }
 
-Certificate::Certificate(sdbusplus::bus::bus& bus, const std::string& objPath,
+Certificate::Certificate(sdbusplus::bus_t& bus, const std::string& objPath,
                          const CertificateType& type,
                          const std::string& installPath, X509_STORE& x509Store,
                          const std::string& pem, Watch* watchPtr,