Apple has started to seed non-developer end-users with a pre-release version of iOS 5.0.1 for testing. According to 9to5Mac, the new software is being offered to a small number of customers who have complained about battery life issues in iOS 5. The invitation email apparently warns that their devices cannot be downgraded to iOS 5.0, but that they will be allowed to upgrade to the final version of iOS 5.0.1 once it’s released. The report goes…