message: Do no shadow dustRelayFee in IsDust() and GetDustThreshHold()
  Also remove references to minRelayTxFee as they are no longer
  relevant.
diff: @@ -144,24 +144,24 @@ public:
  bool IsNull() const { return (nValue == -1); }
  uint256 GetHash() const;
  - CAmount GetDustThreshold(const CFeeRate &minRelayTxFee) const
  + CAmount GetDustThreshold(const CFeeRate &relayFee) const
  {
  - // "Dust" is defined in terms of CTransaction::minRelayTxFee,
  + // "Dust" is defined in terms of the dustRelayFee,
  // which has units satoshis-per-kilobyte.
  // If you'd pay more than 1/3 in fees
  // to spend something, then we consider it dust.
  // A typical spendable txout is 34 bytes big, and will
  // need a CTxIn of at least 148 bytes to spend:
  // so dust is a spendable txout less than
  - // 546*minRelayTxFee/1000 (in satoshis)
  + // 546*dustRelayFee/1000 (in satoshis)
  if (scriptPubKey.IsUnspendable())
  return 0;
  size_t nSize = GetSerializeSize(*this, SER_DISK, 0) + 148u;
  - return 3 * minRelayTxFee.GetFee(nSize);
  + return 3 * relayFee.GetFee(nSize);
  }
  - bool IsDust(const CFeeRate &minRelayTxFee) const { return (nValue < GetDustThreshold(minRelayTxFee)); }
  + bool IsDust(const CFeeRate &_dustRelayFee) const { return (nValue < GetDustThreshold(_dustRelayFee)); }
  friend bool operator==(const CTxOut &a, const CTxOut &b)
  {
  return (a.nValue == b.nValue && a.scriptPubKey == b.scriptPubKey);
  