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: I41103c892db258a85640aa1442acd9a295c8a847
diff --git a/settings.cpp b/settings.cpp
index 8146261..ac99660 100644
--- a/settings.cpp
+++ b/settings.cpp
@@ -18,7 +18,7 @@
 constexpr auto mapperPath = "/xyz/openbmc_project/object_mapper";
 constexpr auto mapperIntf = "xyz.openbmc_project.ObjectMapper";
 
-Objects::Objects(sdbusplus::bus::bus& bus, const Path& root) : bus(bus)
+Objects::Objects(sdbusplus::bus_t& bus, const Path& root) : bus(bus)
 {
     std::vector<std::string> settingsIntfs = {autoRebootIntf, powerRestoreIntf};
     auto depth = 0;
@@ -44,7 +44,7 @@
             elog<InternalFailure>();
         }
     }
-    catch (const sdbusplus::exception::exception& e)
+    catch (const sdbusplus::exception_t& e)
     {
         error("Error in mapper GetSubTree: {ERROR}", "ERROR", e);
         elog<InternalFailure>();
@@ -112,7 +112,7 @@
         auto response = bus.call(mapperCall);
         response.read(result);
     }
-    catch (const sdbusplus::exception::exception& e)
+    catch (const sdbusplus::exception_t& e)
     {
         error("Error in mapper GetObject: {ERROR}", "ERROR", e);
         elog<InternalFailure>();
@@ -127,7 +127,7 @@
     return result.begin()->first;
 }
 
-HostObjects::HostObjects(sdbusplus::bus::bus& bus, size_t id) :
+HostObjects::HostObjects(sdbusplus::bus_t& bus, size_t id) :
     Objects(bus, Path("/xyz/openbmc_project/control/host") + std::to_string(id))
 {}