Service doesn't register to etcd when recovered from network problem or restarting etcd.

[Owen-Zhang]

使用etcd作为注册中心时,如果中间出现网络问题(或者etcd重启)，服务不能重新注册到注册中心

[kevwan]

What's the version of you go-zero?

We've done the fault drill with service discovery. And please check if your ETCD is fully recovered.