message: [Model] Invalid iterator position crash fix.
diff: @@ -491,6 +491,7 @@ QString AddressTableModel::getLastUnusedAddress() const{
  LOCK(wallet->cs_wallet);
  if(!wallet->mapAddressBook.empty()) {
  for (std::map<CTxDestination, CAddressBookData>::iterator it = wallet->mapAddressBook.end(); it != wallet->mapAddressBook.begin(); --it) {
  + if(it != wallet->mapAddressBook.end()) {
  if (it->second.purpose == "receive") {
  const CBitcoinAddress &address = it->first;
  bool fMine = IsMine(*wallet, address.Get());
  @@ -500,6 +501,7 @@ QString AddressTableModel::getLastUnusedAddress() const{
  }
  }
  }
  + }
  return QString();
  }
  