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: I9cedddf4dc9b224ecbc2f68e6b00c0ab1885a826
diff --git a/settings.cpp b/settings.cpp
index 1ac0d9e..b8b3a0d 100644
--- a/settings.cpp
+++ b/settings.cpp
@@ -15,7 +15,7 @@
 constexpr auto mapperPath = "/xyz/openbmc_project/object_mapper";
 constexpr auto mapperIntf = "xyz.openbmc_project.ObjectMapper";
 
-Objects::Objects(sdbusplus::bus::bus& bus) : bus(bus)
+Objects::Objects(sdbusplus::bus_t& bus) : bus(bus)
 {
     std::vector<std::string> settingsIntfs = {timeSyncIntf};
     auto depth = 0;
@@ -36,7 +36,7 @@
         auto response = bus.call(mapperCall);
         response.read(result);
     }
-    catch (const sdbusplus::exception::exception& ex)
+    catch (const sdbusplus::exception_t& ex)
     {
         lg2::error("Failed to invoke GetSubTree method: {ERROR}", "ERROR", ex);
     }
@@ -77,7 +77,7 @@
         auto response = bus.call(mapperCall);
         response.read(result);
     }
-    catch (const sdbusplus::exception::exception& ex)
+    catch (const sdbusplus::exception_t& ex)
     {
         lg2::error("Error in mapper GetObject: {ERROR}", "ERROR", ex);
     }