fix dialyzer

apps/explorer/priv/repo/migrations/20190124082812_add_index_on_transaction_nonce_and_from_address_hash.exs

@@ -1,12 +1,6 @@
 defmodule Explorer.Repo.Migrations.AddIndexOnTransactionNonceAndFromAddressHash do
   use Ecto.Migration
 
-  alias Ecto.Adapters.SQL
-  alias Explorer.Repo
-
-  # 30 minutes
-  @timeout 60_000 * 30
-
   def change do
     create(index(:transactions, [:nonce, :from_address_hash, :block_hash]))
     create(index(:transactions, [:block_hash, :error]))

apps/indexer/lib/indexer/replaced_transaction/fetcher.ex

@@ -90,7 +90,6 @@ defmodule Indexer.ReplacedTransaction.Fetcher do
     Logger.debug("fetching replaced transactions for transactions")
 
     try do
-      {:ok, _} =
       entries
       |> Enum.map(&params/1)
       |> Chain.update_replaced_transactions()