How to delete a photo album added by update

I suspect that in addition to the update you inadvertently did a sync. You can remove the photos from the phone by connecting the phone to the computer, opening iTunes, clicking on the phone under Devices in the left pane of iTunes, then click on Photos in the list across the top of the right pane, and then remove the checkmark in front of "Sync Photos From:" and click the Apply (or Sync) button at the bottom of the page. Each time you sync using iTunes, it sets the non-Camera Roll photos on the phone to match the current settings on the Photos page of iTunes.