Revert of [release-tools] Fix possible race condition in retrieval of latest rolled version

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=

Committed: https://crrev.com/29c575bc7e8b896d566599419e6f73ec349b30fe
Cr-Commit-Position: refs/heads/master@{#29140}

[Michael Hablich, 2015-06-19 09:32:17]

Created Revert of [release-tools] Fix possible race condition in retrieval of
latest rolled version

[commit-bot: I haz the power, 2015-06-19 09:32:28]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1195693003/1

[commit-bot: I haz the power, 2015-06-19 09:32:41]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-06-19 09:33:08]

Patchset 1 (id:??) landed as
https://crrev.com/29c575bc7e8b896d566599419e6f73ec349b30fe
Cr-Commit-Position: refs/heads/master@{#29140}