Revert "Update toolbox base debian image to buster."

This reverts commit d705598525a9dbec58dc82a2b25af0223ac4ec2d.

Reason for revert: Presubmit failed. Create a revert to see whether this is culprit.

Change-Id: I81cc4657e4b62fa47d105ea2ab11cccabdd395ed
Reviewed-on: https://cos-review.googlesource.com/c/cos/overlays/board-overlays/+/8421
Reviewed-by: Saied Kazemi <saied@google.com>
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
2 files changed