When publishing, do not sign and send the snapshot metadata if the
client does not have the snapshot key. If the server sends back
an error, then it also does not have a snapshot key and the
client should propogate the no signing key error.
Signed-off-by: Ying Li <ying.li@docker.com>
Signed-off-by: Ying Li <ying.li@docker.com>
Signed-off-by: David Lawrence <david.lawrence@docker.com>
Signed-off-by: Ying Li <ying.li@docker.com> (github: endophage)