start node with the default BSC genesis block instead of ETH

[weiihann]

Rationale

Whenever a user starts a node, this is what they see:

INFO [11-28|17:14:16.845] Starting Geth on Ethereum mainnet...
...

It's confusing for node operators to see that Geth is running on Ethereum mainnet, even though it's running on BSC mainnet. This is primarily because the --networkid isn't set. In fact, it's not necessary to set it because usually we would parse a config.toml file. However, it'll still be great if we change the default wordings on the logs so it's a better user experience for BSC node operators.

When a user runs geth init from scratch (i.e. sync from genesis block), the default Ethereum genesis block is used. Instead of that, can we use the BSC genesis block as the default block? Or another idea is once the node detects that ETH genesis block is being used, immediately stop the node and let the user know that he/she should do geth init genesis.json first.

Implementation

• Change Ethereum mainnet to BSC mainnet
• Two options:
  • Include the default BSC genesis block data
  • Execute log.Crit if ETH genesis block is being used