Use the SHA1 for a file integrity check
Use the SHA1 for a file integrity check

Signed-off-by: Anthony Emengo <7b3c5a7825e2f856203b8d882230abcb78036abf@pivotal.io>

cloudfoundry/buildpacks-ci,orange-cloudfoundry/buildpacks-ci,cloudfoundry/buildpacks-ci,cloudfoundry/buildpacks-ci,cloudfoundry/buildpacks-ci,orange-cloudfoundry/buildpacks-ci,orange-cloudfoundry/buildpacks-ci,cloudfoundry/buildpacks-ci