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: I9541d521bf67882215a4a66dce020e38ac2df065
diff --git a/utils.hpp b/utils.hpp
index 3a6bad5..8cb8333 100644
--- a/utils.hpp
+++ b/utils.hpp
@@ -48,7 +48,7 @@
  *
  *  @return The value of the property(type: variant)
  *
- *  @throw sdbusplus::exception::exception when it fails
+ *  @throw sdbusplus::exception_t when it fails
  */
 const PropertyValue getProperty(const std::string& objectPath,
                                 const std::string& interface,
@@ -72,7 +72,7 @@
  *
  *  @return The D-Bus paths from the GetSubTree method
  *
- *  @throw sdbusplus::exception::exception when it fails
+ *  @throw sdbusplus::exception_t when it fails
  */
 std::vector<std::string>
     getSubtreePaths(const std::vector<std::string>& interfaces,