remove unused imports in slashing prtection (#2436)

beacon_chain/validators/slashing_protection_v1.nim

@@ -11,7 +11,7 @@ import
   # Status
   eth/db/[kvstore, kvstore_sqlite3],
   chronicles,
-  nimcrypto/[hash, utils],
+  nimcrypto/hash,
   serialization,
   json_serialization,
   # Internal

tests/slashing_protection/test_migration.nim

@@ -1,5 +1,5 @@
 # Nimbus
-# Copyright (c) 2018 Status Research & Development GmbH
+# Copyright (c) 2018-2021 Status Research & Development GmbH
 # Licensed under either of
 #  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or https://www.apache.org/licenses/LICENSE-2.0)
 #  * MIT license ([LICENSE-MIT](LICENSE-MIT) or https://opensource.org/licenses/MIT)
@@ -19,8 +19,7 @@ import
   # Internal
   ../../beacon_chain/validators/[
     slashing_protection,
-    slashing_protection_v1,
-    slashing_protection_v2
+    slashing_protection_v1
   ],
   ../../beacon_chain/spec/[datatypes, digest, crypto, presets],
   # Test utilies