cros_mark_as_stable: Expose the git commit message for use in other scripts.

This way other scripts can find the stable uprev CLs in a reliable way.

BUG=chromium:399356
TEST=ran the cros_mark_as_stable unittests.

Change-Id: I23bda2cad664f23e1ab3177ac8fd6ceba35e23d4
Reviewed-on: https://chromium-review.googlesource.com/226127
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Gabe Black <gabeblack@chromium.org>
Tested-by: Gabe Black <gabeblack@chromium.org>
1 file changed