revert change to shell script
revert change to shell script

- busybox 1.30.x `timeout` uses same arg pattern as coreutils `timeout`

Signed-off-by: Bin Ju <1363c009d7711c2ee2e4c2e46696f32a73a74f21@pivotal.io>
Co-authored-by: Bohan Chen <c9a015a7f6482b47c219aa2cbd78ba6c88c0a327@pivotal.io>

concourse/docker-image-resource,concourse/docker-image-resource