Prevent double removal in staggered strategy

[bitphage]

Closes: #152

[mikakoi]

This isn't a proper fix for the issue, the order needs to be removed from the database when it no longer exists.

[bitphage]

@mikakoi huh? Order actually gets removed a few lines before, I just removed double removal. Look at the full code

    def place_reverse_order(self, order):
        """ Replaces an order with a reverse order
            buy orders become sell orders and sell orders become buy orders
        """
        self.log.info('Change detected, updating orders')
        self.remove_order(order) # <---------------------------- THIS kept

        if order['base']['symbol'] == self.market['base']['symbol']:  # Buy order
            price = order['price'] * (1 + self.spread)
            amount = order['quote']['amount']
            new_order = self.market_sell(amount, price)
        else:  # Sell order
            price = (order['price'] ** -1) / (1 + self.spread)
            amount = order['base']['amount']
            new_order = self.market_buy(amount, price)

        if new_order:
            self.save_order(new_order)
            self.remove_order(order) # <---------------------------- REMOVED

[bitphage]

The real question is, what exactly self.remove_order(order) call should be removed - the first or the second.

[mikakoi]

Oh, silly me. It's the first call that needs to be removed, so that the order isn't removed from the database when an error occurs during the order placement.

[bitphage]

OK, updated a PR.