Remove old and add new migrations (#572)

cumulus/polkadot-parachains/westmint/src/lib.rs

@@ -727,8 +727,9 @@ pub type Executive = frame_executive::Executive<
 pub struct OnRuntimeUpgrade;
 impl frame_support::traits::OnRuntimeUpgrade for OnRuntimeUpgrade {
 	fn on_runtime_upgrade() -> u64 {
-		sp_io::storage::set(b":c", &[]);
-		RocksDbWeight::get().writes(1)
+		frame_support::migrations::migrate_from_pallet_version_to_storage_version::<
+			AllPalletsWithSystem,
+		>(&RocksDbWeight::get())
 	}
 }