Ensure Diego checkout consistent with bosh.io
Ensure Diego checkout consistent with bosh.io

- Also checks out submodules

[#128527087]

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