Modified Geth clients cause problems on ethstats.io

[Incrediblez7]

Describe the bug

Modified geth clients with different consensus.go can connect to ethstats, causing strange data on ethstats.io.

To Reproduce

1. Clone + Compile: https://gitee.com/incrediblez7/go-ethereum
   Changes from the original geth: blockDifficulty = 0, remove block time protection.
2. Sync like normal geth
3. When synced, close and restart using the following flags:
   --maxpeers 0 --ethstats "identity:code@wss://server.ethstats.io" console
   (maxpeers 0 disables network connection with other peers.)
4. do miner.start(1)

Expected behavior

Extremely fast block generation pushed to ethstats.io.

Environment:

Forked geth (https://gitee.com/incrediblez7/go-ethereum)

Possible solution

Disallow all dirty geth clients.