增加sys/debug 部署测试；agent dev/user/instance元信息提取优化；sys/tests 优化 (#26)

Reviewed-on: #26
Reviewed-by: xuxt <xuxt@zgclab.edu.cn>
Reviewed-by: huhy <husteryezi@163.com>
Reviewed-by: sundapeng <sundp@mail.zgclab.edu.cn>

src/bind/build/dns-monitor.sh

@@ -17,6 +17,9 @@ log_message() {
 
 log_message "DNS监控脚本启动"
 
+log_message "删除DNS备份文件（如果存在）"
+rm -f $DNS_BACKUP
+
 while true; do
     if [ -f "$DNS_CONF" ]; then
         if [ -f "$DNS_BACKUP" ]; then