Fix saving of product if price is empty

[seibtph]

No description provided.

[blairwinans]

Thanks, @seibtph! Could you just update this to potentially just check for whether $objProduct->getPrice() is null and if so pass 0 to Isotope::formatPriceWithCurrency() so that a price gets set on the $objItem, even if it is 0?

Otherwise I don't think the feed item will be valid. Come to think of it, since I don't think the item would be valid without a price anyhow, should we instead check for this further up in the if($objProduct->isPublished() && $objProduct->useFeed) statement? I think that may be the better way to handle it because I am almost positive a zero-price will not be valid in the feed?