message: Ensure new DSProof is valid
  A check in DoubleSpendProof::validate() was incorrectly
  testing whether prevOutIndex >= spendingTx.vout.size(), and if so,
  marking the proof as invalid.  This is not correct.  The spending OUTPUT
  index has nothing to do with the PREVOUT index!  Likely a brain error
  ocurred here. :)
diff: @@ -235,7 +235,7 @@ DoubleSpendProof::Validity DoubleSpendProof::validate(const CTxMemPool &pool, co
  if (ptx == nullptr)
  {
  auto it = pool.mapNextTx.find({m_prevTxId, (uint32_t)m_prevOutIndex});
  - if (it == pool.mapNextTx.end() || (size_t)m_prevOutIndex >= it->second.ptx->vout.size())
  + if (it == pool.mapNextTx.end())
  {
  return MissingTransaction;
  }
  