message: [Wallet] Initialize zwalletMain to prevent memory access violations if it's not set.
diff: @@ -608,8 +608,8 @@ public:
  std::map<libzerocoin::CoinDenomination, CAmount> GetMyZerocoinDistribution() const;
  // zPIV wallet
  - CzPIVWallet* zwalletMain;
  - std::unique_ptr<CzPIVTracker> zpivTracker;
  + CzPIVWallet* zwalletMain{nullptr};
  + std::unique_ptr<CzPIVTracker> zpivTracker{nullptr};
  void setZWallet(CzPIVWallet* zwallet);
  CzPIVWallet* getZWallet();
  bool IsMyZerocoinSpend(const CBigNum& bnSerial) const;
  