chromeos_config: Add usepkg_toolchain=False to lakitu template

We backported a patch for Go 1.8:
https://crrev.com/c/615754
This flag is needed so that the release branch will rebuild the
Go compiler with the patch.

BUG=b:64542183
TEST=trybot

Change-Id: I582a7dee63943ee0fc156221a768112cd1eb91f5
Reviewed-on: https://chromium-review.googlesource.com/641869
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Ke Wu <mikewu@google.com>
Tested-by: Ke Wu <mikewu@google.com>
2 files changed