message: Don't contextual check mint unless output is mint.
diff: @@ -796,8 +796,10 @@ static bool AcceptToMemoryPoolWorker(const CChainParams& chainparams, CTxMemPool
  }
  //Do context checks of mint
  - if (!setPubcoins.empty()) {
  + if (pout->IsZerocoinMint() && !setPubcoins.empty()) {
  libzerocoin::PublicCoin pubcoin(Params().Zerocoin_Params());
  + if (!OutputToPublicCoin(pout.get(), pubcoin))
  + return state.Invalid(false, REJECT_INVALID, "zcmint-malformed");
  if (!OutputToPublicCoin(pout.get(), pubcoin) || !ContextualCheckZerocoinMint(tx, pubcoin, chainActive.Tip()))
  return state.Invalid(false, REJECT_INVALID, "zcmint-fail-context-check");
  }
  