Changes for substrate#3699 (#466)

* change upstream and branch

* Fix build

* remove doc renamings

* Fix tests

* .

* Revert changing fork and branch

* Update Cargo.toml

* Update parachains.rs

polkadot/runtime/src/lib.rs

@@ -521,6 +521,7 @@ construct_runtime!(
 	{
 		// Basic stuff; balances is uncallable initially.
 		System: system::{Module, Call, Storage, Config, Event},
+		RandomnessCollectiveFlip: randomness_collective_flip::{Module, Storage},
 
 		// Must be before session.
 		Babe: babe::{Module, Call, Storage, Config, Inherent(Timestamp)},
@@ -629,7 +630,7 @@ impl_runtime_apis! {
 		}
 
 		fn random_seed() -> <Block as BlockT>::Hash {
-			System::random_seed()
+			RandomnessCollectiveFlip::random_seed()
 		}
 	}