cros_util: fix up naming

Since these two scripts are tracking upstream Chrome OS repos,
fixing naming is a bit harder. This patch creates a variable to
hold the name of the main branch, so it's easier to fix these
files in case any future name fixing on upstream.

Also run `yapf` during presubmit.

BUG=chromium:1099035
TEST=None

Change-Id: Ic72a213dadf12b382a76fe50d48cde6fcecc3b25
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/2270728
Reviewed-by: Caroline Tice <cmtice@chromium.org>
Commit-Queue: Tiancong Wang <tcwang@google.com>
Tested-by: Tiancong Wang <tcwang@google.com>
2 files changed