Move node default_versions updating functionality to correct method
Move node default_versions updating functionality to correct method

[#130202321]

Signed-off-by: Anna Thornton <0e9b4a17e1cf85a71a11118ecdbc866e5f8ffc65@pivotal.io>

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