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/bmc_state_manager.cpp b/bmc_state_manager.cpp
index 85eb3cf..e1cbaf2 100644
--- a/bmc_state_manager.cpp
+++ b/bmc_state_manager.cpp
@@ -59,7 +59,7 @@
         auto result = this->bus.call(method);
         result.read(unitTargetPath);
     }
-    catch (const sdbusplus::exception::exception& e)
+    catch (const sdbusplus::exception_t& e)
     {
         // Not all input units will have been loaded yet so just return an
         // empty string if an exception is caught in this path
@@ -81,7 +81,7 @@
         // Is input target active or inactive?
         result.read(currentState);
     }
-    catch (const sdbusplus::exception::exception& e)
+    catch (const sdbusplus::exception_t& e)
     {
         info("Error in ActiveState Get: {ERROR}", "ERROR", e);
         return std::string{};
@@ -125,7 +125,7 @@
     {
         this->bus.call(method);
     }
-    catch (const sdbusplus::exception::exception& e)
+    catch (const sdbusplus::exception_t& e)
     {
         error("Failed to subscribe to systemd signals: {ERROR}", "ERROR", e);
         elog<InternalFailure>();
@@ -151,7 +151,7 @@
         {
             this->bus.call(method);
         }
-        catch (const sdbusplus::exception::exception& e)
+        catch (const sdbusplus::exception_t& e)
         {
             info("Error in HardReboot: {ERROR}", "ERROR", e);
         }
@@ -181,7 +181,7 @@
         {
             this->bus.call(method);
         }
-        catch (const sdbusplus::exception::exception& e)
+        catch (const sdbusplus::exception_t& e)
         {
             info("Error in StartUnit - replace-irreversibly: {ERROR}", "ERROR",
                  e);
@@ -190,7 +190,7 @@
     return;
 }
 
-int BMC::bmcStateChange(sdbusplus::message::message& msg)
+int BMC::bmcStateChange(sdbusplus::message_t& msg)
 {
     uint32_t newStateID{};
     sdbusplus::message::object_path newStateObjPath;
@@ -215,7 +215,7 @@
         {
             this->bus.call(method);
         }
-        catch (const sdbusplus::exception::exception& e)
+        catch (const sdbusplus::exception_t& e)
         {
             info("Error in Unsubscribe: {ERROR}", "ERROR", e);
         }