Make necessary change to make things work with photon 2.0 docker image.
Remove distro-sync to mitigate the build issue and add `--pull` to docker build
command to make sure the latest photon:2.0 will be pulled during build process.
Signed-off-by: Daniel Jiang <jiangd@vmware.com>
docker regsitry. This version has the API to call regsitry GC with jobservice
secret. Seprates it into a standalone container as do not want to invoke two
processes in one container.
It needs to mount the registry storage into this container in order to do GC,
and needs to copy the registry binary into it.
