message: wallet/wallet.h: Remove mutexScanning which was only protecting a single atomic bool
diff: @@ -619,7 +619,6 @@ private:
  std::atomic<bool> fScanningWallet{false}; // controlled by WalletRescanReserver
  std::atomic<int64_t> m_scanning_start{0};
  std::atomic<double> m_scanning_progress{0};
  - std::mutex mutexScanning;
  friend class WalletRescanReserver;
  //! the current wallet version: clients below this version are not able to load the wallet
  @@ -1266,13 +1265,11 @@ public:
  bool reserve()
  {
  assert(!m_could_reserve);
  - std::lock_guard<std::mutex> lock(m_wallet.mutexScanning);
  - if (m_wallet.fScanningWallet) {
  + if (m_wallet.fScanningWallet.exchange(true)) {
  return false;
  }
  m_wallet.m_scanning_start = GetTimeMillis();
  m_wallet.m_scanning_progress = 0;
  - m_wallet.fScanningWallet = true;
  m_could_reserve = true;
  return true;
  }
  @@ -1284,7 +1281,6 @@ public:
  ~WalletRescanReserver()
  {
  - std::lock_guard<std::mutex> lock(m_wallet.mutexScanning);
  if (m_could_reserve) {
  m_wallet.fScanningWallet = false;
  }
  