Replace reflect with type assertion
Replace reflect with type assertion

conceptboard/packer,xenserverarmy/packer,dongyuzheng/packer-builder-xenserver,xenserverarmy/packer,fr34k8/packer-builder-xenserver,fr34k8/packer-builder-xenserver,june07/packer-builder-xenserver,makunterry/packer-builder-xenserver,june07/packer-builder-xenserver,simonfuhrer/packer-builder-xenserver-1,conceptboard/packer,rdobson/packer-builder-xenserver,simonfuhrer/packer-builder-xenserver-1,rdobson/packer-builder-xenserver,makunterry/packer-builder-xenserver,dongyuzheng/packer-builder-xenserver