message: Fix for listaddressgroupings with private spends
diff: @@ -7393,6 +7393,8 @@ set <set<CTxDestination>> CWallet::GetAddressGroupings() {
  BOOST_FOREACH(CTxIn txin, pcoin->vin)
  {
  CTxDestination address;
  + if (txin.IsZerocoinSpend() || txin.IsSigmaSpend()) /* Spends have no standard input */
  + continue;
  if (!IsMine(txin)) /* If this input isn't mine, ignore it */
  continue;
  if (!ExtractDestination(mapWallet[txin.prevout.hash].vout[txin.prevout.n].scriptPubKey, address))
  