Revert of [release-tools] Fix possible race condition in retrieval of latest rolled version (patchset #2 id:20001 of https://codereview.chromium.org/1186393007/)

Reason for revert:
Build slave fetches git repo from cache not from real repo.

Original issue's description:
> [release-tools] Fix possible race condition in retrieval of latest rolled version
>
> R=machenbach@chromium.org
> BUG=
> NOTRY=true
>
> Committed: https://crrev.com/5d2a85b2450f9f88a94949052c5b055c1304b9b8
> Cr-Commit-Position: refs/heads/master@{#29137}

TBR=machenbach@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=

Review URL: https://codereview.chromium.org/1195693003

Cr-Commit-Position: refs/heads/master@{#29140}