Fix irrelevant receipt status message

Since security level has been removed, this status message needed to be
changed.

Also removed some stale unused code that was left over from when
security level was used.

src/wallet.cpp

@@ -4744,7 +4744,7 @@ bool CWallet::MintsToInputVector(std::map<CBigNum, CZerocoinMint>& mapMintsSelec
 
             // Generate the witness for each mint being spent
             if (!GenerateAccumulatorWitness(coinWitness, mapAccumulators, pindexCheckpoint)) {
-                receipt.SetStatus(_("Try to spend with a higher security level to include more coins"),
+                receipt.SetStatus(_("Couldn't generate the accumulator witness"),
                                   ZPIV_FAILED_ACCUMULATOR_INITIALIZATION);
                 return error("%s : %s", __func__, receipt.GetStatusMessage());
             }
@@ -5003,13 +5003,6 @@ bool CWallet::CreateZerocoinSpendTransaction(CAmount nValue, CWalletTx& wtxNew,
             //hash with only the output info in it to be used in Signature of Knowledge
             uint256 hashTxOut = txNew.GetHash();
 
-            //Use the same accumulator checkpoint for each spend
-            int nHeightHighest = 0;
-            for (const CZerocoinMint& mint : vSelectedMints) {
-                if (mint.GetHeight() > nHeightHighest)
-                    nHeightHighest = mint.GetHeight();
-            }
-
             CBlockIndex* pindexCheckpoint = nullptr;
             std::map<CBigNum, CZerocoinMint> mapSelectedMints;
             for (const CZerocoinMint& mint : vSelectedMints)