deliver events with the core thread pool set events-use-dispatch=true in switch.conf.xml to use the old way

src/include/private/switch_core_pvt.h

@@ -275,6 +275,7 @@ struct switch_runtime {
 	char *core_db_post_trans_execute;
 	char *core_db_inner_pre_trans_execute;
 	char *core_db_inner_post_trans_execute;
+	int events_use_dispatch;
 };
 
 extern struct switch_runtime runtime;