Add `Exception` namespace to autoload
Add `Exception` namespace to autoload

Add the `ZendService\Apple\Exception` namespace handler to the autoload
configuration. It is not under the `Apns` namespace that the existing
configuration handles.

boboldehampsink/ZendService_Apple_Apns,Doka-NT/ZendService_Apple_Apns,barryvdh/ZendService_Apple_Apns,telemaque/ZendService_Apple_Apns,nagodon/ZendService_Apple_Apns