Sync alpha and beta tags
This is for syncing hyperkube alpha and beta tags for testing new Kubernetes versions.
These are the new hyperkube images that were synced by the CI running on this branch, all other alpha/beta releases had already been synced:
$ cat job_sync_hyperkube.log | grep "syncing" | grep -v "exists"
syncing gcr.io/google-containers % hyperkube % v1.15.11-beta.0
syncing gcr.io/google-containers % hyperkube % v1.16.8-beta.0
syncing gcr.io/google-containers % hyperkube % v1.17.4-beta.0
syncing gcr.io/google-containers % hyperkube % v1.18.0-alpha.5
syncing gcr.io/google-containers % hyperkube % v1.18.0-beta.0
syncing gcr.io/google-containers % hyperkube % v1.18.0-beta.1
syncing gcr.io/google-containers % hyperkube % v1.18.0-beta.2
syncing gcr.io/google-containers % hyperkube % v1.19.0-alpha.0
end syncing gcr.io/google-containers/hyperkube
I also included a commit to fix the retry logic, since it would never actually retry.