This reverts commit 01f0c698.

Reason for revert: https://chromium-review.googlesource.com/c/chromium/tools/build/+/1211422

Original change's description:
> bot_update: Specify the target branch for patch_refs.
> 
> Bug: 870279
> Recipe-Manual-Change: build
> Recipe-Manual-Change: infra
> Recipe-Manual-Change: build_limited_scripts_slave
> Recipe-Manual-Change: skia
> Recipe-Manual-Change: release_scripts
> Change-Id: I58110ff8c5a6ca6906bbbf3eafa09dcbaf39f777
> Reviewed-on: https://chromium-review.googlesource.com/1174988
> Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>
> Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>

TBR=tandrii@chromium.org,ehmaldonado@chromium.org,jbudorick@chromium.org

Change-Id: Ic78a264ccf5e2ca15452659e17d41da264560eb8
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 870279
Reviewed-on: https://chromium-review.googlesource.com/1211462Reviewed-by: Nodir Turakulov <nodir@chromium.org>
Commit-Queue: Nodir Turakulov <nodir@chromium.org>