Go back to regular git diff in sync-package-specs
Go back to regular git diff in sync-package-specs

[finishes #154032983]

Signed-off-by: Will Pragnell <eefda05bdef438660d447ff971b84a00b7795fad@pivotal.io>

cloudfoundry-incubator/diego-release,cloudfoundry-incubator/diego-release,cloudfoundry-incubator/diego-release,cloudfoundry-incubator/diego-release