test ca_certs_for_downloads works the same as tls.ca_cert property
test ca_certs_for_downloads works the same as tls.ca_cert property

[#140818681]

Signed-off-by: Chris Piraino <f047703f03f13cc8e1b226aa8ba85c2dfc238f94@pivotal.io>

cloudfoundry-incubator/inigo