Remove migration code. (#5291)

* Remove migration code.

* Fix cargo

* Bump spec version

substrate/frame/grandpa/src/lib.rs

@@ -151,13 +151,6 @@ decl_error! {
 
 decl_storage! {
 	trait Store for Module<T: Trait> as GrandpaFinality {
-		/// DEPRECATED
-		///
-		/// This used to store the current authority set, which has been migrated to the well-known
-		/// GRANDPA_AUTHORITIES_KEY unhashed key.
-		#[cfg(feature = "migrate-authorities")]
-		pub(crate) Authorities get(fn authorities): AuthorityList;
-
 		/// State of the current authority set.
 		State get(fn state): StoredState<T::BlockNumber> = StoredState::Live;
 
@@ -184,15 +177,6 @@ decl_storage! {
 	}
 }
 
-mod migration {
-	use super::*;
-	pub fn migrate<T: Trait>() {
-		for i in 0..=CurrentSetId::get() {
-			SetIdSession::migrate_key_from_blake(i);
-		}
-	}
-}
-
 decl_module! {
 	pub struct Module<T: Trait> for enum Call where origin: T::Origin {
 		type Error = Error<T>;
@@ -205,15 +189,6 @@ decl_module! {
 			// FIXME: https://github.com/paritytech/substrate/issues/1112
 		}
 
-		fn on_runtime_upgrade() {
-			migration::migrate::<T>();
-		}
-
-		fn on_initialize() {
-			#[cfg(feature = "migrate-authorities")]
-			Self::migrate_authorities();
-		}
-
 		fn on_finalize(block_number: T::BlockNumber) {
 			// check for scheduled pending authority set changes
 			if let Some(pending_change) = <PendingChange<T>>::get() {
@@ -384,13 +359,6 @@ impl<T: Trait> Module<T> {
 			Self::set_grandpa_authorities(authorities);
 		}
 	}
-
-	#[cfg(feature = "migrate-authorities")]
-	fn migrate_authorities() {
-		if Authorities::exists() {
-			Self::set_grandpa_authorities(&Authorities::take());
-		}
-	}
 }
 
 impl<T: Trait> Module<T> {