Remote Backup User Plugin "remoteBackup.groovy" did not work for the docker repo

[gyzong1]

Remote Backup User Plugin "remoteBackup.groovy" did not work for the docker repo, only manifest.json has been copied, and the image layers were not copied.

Reproduction steps:

1. Create two docker repositories "docker-local" and "docker-local-copy"
2. Deploy user plugin "remoteBackup.groovy" and configuration file "remoteBackup.json"
3. Push docker image to docker-local via "docker push localhost:8082/docker-local/busybox:v1"
4. Check "docker-local-copy", only the manifest.json has been copied
   

Request support for docker-type repositories.