Revert of Use script in depot_tools to retrieve builders from new cq.cfg

Revert of Use script in depot_tools to retrieve builders from new cq.cfg (patchset #10 id:180001 of https://codereview.chromium.org/1152823005/)

Reason for revert:
Speculative, looks like this broke `git cl try` for me (crbug.com/495219)

Original issue's description:
> Use script in depot_tools to retrieve builders from new cq.cfg
>
> R=pgervais@chromium.org
> TEST=ran git-cl-try on this CL
>
> Committed: https://crrev.com/87e80c7a628381644013e3b96b437276d9b19bcd
> Cr-Commit-Position: refs/heads/master@{#332200}

TBR=jochen@chromium.org,brettw@chromium.org,cpu@chromium.org,jam@chromium.org,pgervais@chromium.org,sergiyb@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Committed: https://crrev.com/4090c5cf35c931faf6c165373a940ee05950ffa9
Cr-Commit-Position: refs/heads/master@{#332232}

[Nico, 2015-06-01 19:08:26]

Created Revert of Use script in depot_tools to retrieve builders from new cq.cfg

[commit-bot: I haz the power, 2015-06-01 19:12:40]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1147003007/1

[commit-bot: I haz the power, 2015-06-01 19:16:29]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-06-01 19:18:11]

Patchset 1 (id:??) landed as
https://crrev.com/4090c5cf35c931faf6c165373a940ee05950ffa9
Cr-Commit-Position: refs/heads/master@{#332232}

[pgervais, 2015-08-03 20:42:03]

On 2015/06/01 19:18:11, commit-bot: I haz the power wrote:
> Patchset 1 (id:??) landed as
> https://crrev.com/4090c5cf35c931faf6c165373a940ee05950ffa9
> Cr-Commit-Position: refs/heads/master@{#332232}

lgtm (just to clear my list of TBR'd commits not acked)