Revert "USE local lock for buildbot_test_toolchain."

This reverts commit 4260aae2fe0abb937543c6cafc44f68e99de7410.

Reason for revert: afe_lock_machine is fixed.

Original change's description:
> USE local lock for buildbot_test_toolchain.
> 
> Currently the AFE lock machanism for our nightly test is broken,
> we use local lock as a workaround for now.
> 
> BUG=chromium:762589
> TEST=Generate the crosperf command in another simple python file
>      with the same code. Run the generated command line on
>      crotomation2 and it goes though the locking machine stage.
> 
> Change-Id: Icd3132bc383b63aab6d6f5237a04348f11d8726d
> Reviewed-on: https://chromium-review.googlesource.com/653213
> Commit-Ready: Yunlian Jiang <yunlian@chromium.org>
> Tested-by: Yunlian Jiang <yunlian@chromium.org>
> Reviewed-by: Caroline Tice <cmtice@chromium.org>

Bug: chromium:762589
Change-Id: Ib9f787ff48953d384dd36c72811ebd0f20dd25db
Reviewed-on: https://chromium-review.googlesource.com/1178897
Tested-by: Ting-Yuan Huang <laszio@chromium.org>
Reviewed-by: Luis Lozano <llozano@chromium.org>
Reviewed-by: Caroline Tice <cmtice@chromium.org>
Commit-Queue: Ting-Yuan Huang <laszio@chromium.org>
diff --git a/buildbot_test_toolchains.py b/buildbot_test_toolchains.py
index e5674a2..bf3a8de 100755
--- a/buildbot_test_toolchains.py
+++ b/buildbot_test_toolchains.py
@@ -213,9 +213,7 @@
     crosperf = os.path.join(TOOLCHAIN_DIR, 'crosperf', 'crosperf')
     noschedv2_opts = '--noschedv2' if self._noschedv2 else ''
     command = ('{crosperf} --no_email=True --results_dir={r_dir} '
-               '--json_report=True {noschedv2_opts} {exp_file} '
-               '--locks_dir=/usr/local/google/home/mobiletc-prebuild/locks '
-               '--use_file_locks=True').format(
+               '--json_report=True {noschedv2_opts} {exp_file}').format(
                    crosperf=crosperf,
                    r_dir=self._reports_dir,
                    noschedv2_opts=noschedv2_opts,