exception: switch sdbusplus type

The exceptions defined in error-HostEvent.hpp are "by-hand" versions
of classes that would come from sdbus++/PDI.  sdbusplus now uses a
different exception base class for generated exceptions[1], so switch
the local versions here to match.

1. https://github.com/openbmc/sdbusplus/commit/15228663a1e1f27729a5e55c8d775f3537ab8444

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I713e0376b5cc60e6ffc865925b87eb9df4669b7c
diff --git a/error-HostEvent.hpp b/error-HostEvent.hpp
index 72dc6e9..783aedd 100644
--- a/error-HostEvent.hpp
+++ b/error-HostEvent.hpp
@@ -13,7 +13,7 @@
 namespace Error
 {
 
-struct Event final : public sdbusplus::exception_t
+struct Event final : public sdbusplus::exception::generated_exception
 {
     static constexpr auto errName = "org.open_power.Host.Error.Event";
     static constexpr auto errDesc = "A host system event was received";
@@ -25,7 +25,8 @@
     const char* what() const noexcept override;
 };
 
-struct MaintenanceProcedure final : public sdbusplus::exception_t
+struct MaintenanceProcedure final
+    : public sdbusplus::exception::generated_exception
 {
     static constexpr auto errName =
         "org.open_power.Host.Error.MaintenanceProcedure";