message: Create op sender transaction when op sender is activated
diff: #include <wallet/walletdb.h>
  #include <wallet/walletutil.h>
  #include <miner.h>
  +#include <chainparams.h>
  #include <stdint.h>
  @@ -809,6 +810,11 @@ static UniValue createcontract(const JSONRPCRequest& request){
  }
  else
  {
  + // Create op sender transaction when op sender is activated
  + int nHeight = chainActive.Height();
  + if(!(nHeight >= Params().GetConsensus().QIP5Height))
  + throw JSONRPCError(RPC_TYPE_ERROR, "Sender address does not have any unspent outputs");
  +
  // Sign the sender in case of no UTXO
  signSenderAddress = senderAddress;
  }
  @@ -1043,6 +1049,11 @@ static UniValue sendtocontract(const JSONRPCRequest& request){
  }
  else
  {
  + // Create op sender transaction when op sender is activated
  + int nHeight = chainActive.Height();
  + if(!(nHeight >= Params().GetConsensus().QIP5Height))
  + throw JSONRPCError(RPC_TYPE_ERROR, "Sender address does not have any unspent outputs");
  +
  // Sign the sender in case of no UTXO
  signSenderAddress = senderAddress;
  }
  