Multiple occurrences of IAP not passing and restore returning: Cannot connect to iTunes Store

### Platform

- [x] iOS
- [ ] macOS
- [ ] tvOS

### In app purchase type

- [ ] Consumable
- [x] Non-consumable
- [ ] Auto-Renewable Subscription
- [ ] Non-Renewing Subscription

### Environment

- [ ] Sandbox
- [x] Production

### Version
running on `swift-2.3` branch

### Related issues
#140 but contrary to that person I cannot reproduce myself this error. But it happens to about 25% of my transactions which is a big deal at the moment. (Last week on 50 transactions I got about 9 of them who got that error).

## Report

### Issue summary
Multiple customers are emailing us about not being able to purchase our IAP for our PRO version.

One said "i buyed the pro version, but the ads still on. And App says nothing to restore."

Basically, we have a buy pro version in the app's preferences. When they press on it a call to SwiftyStoreKit.purchaseProduct is done.

When he tries to restore, results.restoreFailedProducts = `[(Error Domain=SKErrorDomain Code=2 "Cannot connect to iTunes Store" UserInfo={NSLocalizedDescription=Cannot connect to iTunes Store}, nil)]`

### What did you expect to happen
Transactions should pass and when they do they should and result in errors they should at least be restorable if the initial transaction went okay.

### What happened instead
Purchase never seems to pass.
Restore returns a cannot connect to itunes store error.
Leaving the customer without any way of getting the product.

---

Just for more information, I added both my purchase and restore methods here. Feel free to ask for more details. Please don't mind the debug calls.

```
static func purchasePro() {
SwiftyStoreKit.purchaseProduct(ProProductIdentifier) { result in
switch result {
case .Success(let productId):
self.hasPurchasedPro()
// reloading UI to get rid of ads
self.reloadAdUI()
if Consts.DebugPurchases {
self.notificationHandler.displayAlert("Purchase Success", message: "\(productId)", type: .Success)
} else {
// logging event
LoggingHandler.reportEvent("PurchaseProSuccess", customData: ["productId": "\(productId)"])
}
case .Error(let error):
if Consts.DebugPurchases {
self.notificationHandler.displayAlert("Purchase Failed", message: "\(error)", type: .Danger)
} else {
// logging event
LoggingHandler.reportEvent("PurchaseProFailed", customData: ["error": "\(error)"])
}
}
}
}

static func restorePurchase(silenced: Bool) {
// trying to restore something
SwiftyStoreKit.restorePurchases() { results in
if results.restoreFailedProducts.count > 0 {
// if debug, display response
if Consts.DebugPurchases {
self.notificationHandler.displayAlert("Restore Failed", message: "\(results.restoreFailedProducts)", type: .Danger)
} else {
// silence this notification and logging
if !silenced {
// contact support if this seems wrong
self.notificationHandler.displayAlert("restore_error".localized(), message: "nothing_to_restore_is_it_wrong".localized(), type: .Danger)
// logging event
LoggingHandler.reportEvent("RestoreFailed", customData: ["restoreFailedProducts": "\(results.restoreFailedProducts)"])
}
}
} else if results.restoredProductIds.count > 0 {
// mark user as pro and reload ui
self.hasPurchasedPro()
self.reloadAdUI()
// if debug, display response
if Consts.DebugPurchases {
self.notificationHandler.displayAlert("Restore Success", message: "\(results.restoredProductIds)", type: .Success)
} else {
// logging event
LoggingHandler.reportEvent("RestoreSuccess", customData: ["restoredProductIds": "\(results.restoredProductIds)"])
}
} else {
// silence this notification
if !silenced {
self.notificationHandler.displayAlert("restore_error".localized(), message: "nothing_to_restore".localized(), type: .Danger)
}
}
}
}
```