Fix fast-runtime

[zjb0807]

There have prod_or_fast and fast-runtime feature, so revert #2167

[bkchr]

I don't see any reason why this should be done. This changes the behavior in quite some way.

[zjb0807]

I don't see any reason why this should be done. This changes the behavior in quite some way.

polkadot/runtime/rococo/constants/src/lib.rs

Lines 40 to 43 in a13f0b9

	pub const DEFAULT_EPOCH_DURATION: BlockNumber = prod_or_fast!(1 * HOURS, 1 * MINUTES);
	frame_support::parameter_types! {
	pub storage EpochDurationInBlocks: BlockNumber = DEFAULT_EPOCH_DURATION;
	}

prod_or_fast was used here, but the EpochDurationInBlocks was modified in chain_spec.rs. It's going to be a little confusing

[zjb0807]

I need a stable rococo-local network to test para chain, EPOCH_DURATION is 1min and will cause UnexpectedEpochChange.

[bkchr]

I need a stable rococo-local network to test para chain, EPOCH_DURATION is 1min and will cause UnexpectedEpochChange.

I never had problems with 1 minute epochs. However, your change here would also just lead to 1 minute epochs when you use fast. You clearly don't want to wait 1 hour until your Parachain is onboarded. With the current code, you can also change the epoch/session length in the chain spec.

[bkchr]

bot merge

[paritytech-processbot]

Waiting for commit status.