cleanup a few more rlpHash calls (#2359)

fluffy/eth_data/era1.nim

@@ -467,7 +467,7 @@ proc verify*(f: Era1File): Result[Digest, string] =
         ?f.getBlockTuple(blockNumber)
 
       txRoot = calcTxRoot(blockBody.transactions)
-      ommershHash = keccakHash(rlp.encode(blockBody.uncles))
+      ommershHash = rlpHash(blockBody.uncles)
 
     if blockHeader.txRoot != txRoot:
       return err("Invalid transactions root")

fluffy/network/state/state_validation.nim

@@ -24,7 +24,7 @@ proc isValidNextNode(
   let nextHash =
     if hashOrShortRlp.isList():
       # is a short node
-      keccakHash(rlp.encode(hashOrShortRlp))
+      rlpHash(hashOrShortRlp)
     else:
       let hash = hashOrShortRlp.toBytes()
       if hash.len() != 32:

fluffy/rpc/rpc_eth_api.nim

@@ -119,7 +119,7 @@ func init*(
         inc i
     else:
       for tx in body.transactions:
-        blockObject.transactions.add txOrHash(w3Hash keccakHash(rlp.encode(tx)))
+        blockObject.transactions.add txOrHash(w3Hash rlpHash(tx))
 
   blockObject