parachain-system: Send same event & digest as a standalone chain (par…

…itytech#2064)

This ensures that upgrading a parachain code sends the same event &
digest as when using `set_code` on a standalone chain.

Close: paritytech#2049

substrate/frame/system/src/lib.rs

@@ -163,7 +163,7 @@ pub trait SetCode<T: Config> {
 
 impl<T: Config> SetCode<T> for () {
 	fn set_code(code: Vec<u8>) -> DispatchResult {
-		<Pallet<T>>::update_code_in_storage(&code)?;
+		<Pallet<T>>::update_code_in_storage(&code);
 		Ok(())
 	}
 }
@@ -1106,11 +1106,10 @@ impl<T: Config> Pallet<T> {
 	/// Note this function almost never should be used directly. It is exposed
 	/// for `OnSetCode` implementations that defer actual code being written to
 	/// the storage (for instance in case of parachains).
-	pub fn update_code_in_storage(code: &[u8]) -> DispatchResult {
+	pub fn update_code_in_storage(code: &[u8]) {
 		storage::unhashed::put_raw(well_known_keys::CODE, code);
 		Self::deposit_log(generic::DigestItem::RuntimeEnvironmentUpdated);
 		Self::deposit_event(Event::CodeUpdated);
-		Ok(())
 	}
 
 	/// Increment the reference counter on an account.