add core-db-pre-trans-execute and core-db-post-trans-execute to switch.conf.xml to wrap sql stmts around the core transactions

src/include/private/switch_core_pvt.h

@@ -261,6 +261,8 @@ struct switch_runtime {
 	uint32_t db_handle_timeout;
 	int cpu_count;
 	uint32_t time_sync;
+	char *core_db_pre_trans_execute;
+	char *core_db_post_trans_execute;
 };
 
 extern struct switch_runtime runtime;