Address warnings.

- switch to using UIAlertController
- assign an identifier to segue

Mobile Buy SDK Sample Apps/Sample App Customers/Sample App Customers/AccountViewController.swift

@@ -85,6 +85,8 @@ extension AccountViewController: AuthenticationDelegate {
     }
     
     func authenticationDidFailWithError(error: NSError?) {
-        UIAlertView(title: "Error", message: error?.localizedDescription, delegate: nil, cancelButtonTitle: "OK").show()
+        let alert = UIAlertController(title: "Error", message: error?.localizedDescription, preferredStyle: .Alert)
+        alert.addAction(UIAlertAction(title: "OK", style: .Cancel, handler: nil))
+        self.presentViewController(alert, animated: true, completion: nil)
     }
 }

Mobile Buy SDK Sample Apps/Sample App Customers/Sample App Customers/Base.lproj/Main.storyboard

@@ -78,7 +78,7 @@
                     <connections>
                         <outlet property="loginContainerView" destination="KZD-y5-2e3" id="g1r-NW-TfQ"/>
                         <outlet property="signupContainerView" destination="ZAC-pf-9Yj" id="GGw-ff-lV9"/>
-                        <segue destination="gsn-tk-U20" kind="show" id="cw5-XQ-PCc"/>
+                        <segue destination="gsn-tk-U20" kind="show" identifier="ordersSegue" id="cw5-XQ-PCc"/>
                     </connections>
                 </viewController>
                 <placeholder placeholderIdentifier="IBFirstResponder" id="twZ-kb-vHr" userLabel="First Responder" sceneMemberID="firstResponder"/>