TOOLS-980: sdcadm Failure on "image not found" in Milan-B
TOOLS-980: sdcadm Failure on "image not found" in Milan-B

Search for candidate image by 'published_at' as we really always wnated
too, now that updates.jo has support for this via IMGAPI-477.

joyent/sdcadm,joyent/sdcadm,joyent/sdcadm