/topology/tidb/{addr}/info should be cleaned after ttl

## Bug Report

See https://github.com/pingcap/tidb/pull/14809#discussion_r382475320

### 1. Minimal reproduce step (Required)

### 2. What did you expect to see? (Required)

This info should be put with lease so that it can be cleaned automatically.

### 3. What did you see instead (Required)

We have to clean the record by external tools. e.g. https://github.com/pingcap/tidb-operator/issues/3697

### 4. What is your TiDB version? (Required)