The previous code assumed that the link returned when listing tags was
always absolute. However, some registries, such as quay.io, return the
link as a relative link (e.g. the second page for the quay.io/coreos/etcd
image is /v2/coreos/etcd/tags/list?next_page=<truncated>&n=50). Because
the relative link was retrieved directly, the fetch failed (with the
error `unsupported protocol scheme ""`).
Signed-off-by: Kevin Lin <kevin@kelda.io>
1bfbeca726