[autotest] Bump the stable repair build to R40-6450.0.0.

The previous stable repair build (R39-6298.0.0.) was found to be
poisonous for storm. I have it on good faith that anything post
R40-6432.0.0 is enough, though we don't have data to correlate
since we don't run bvts on storm yet.

R40-6450.0.0 passed bvts on all boards, so it's good enough for now.

BUG=chromium:433132
TEST=Build passed canary bvt on all boards.

Change-Id: I6c171bbc398447a45a202d5dad77e086e88c9299
Reviewed-on: https://chromium-review.googlesource.com/229701
Reviewed-by: Richard Barnette <jrbarnette@chromium.org>
Commit-Queue: Prashanth B <beeps@chromium.org>
Tested-by: Prashanth B <beeps@chromium.org>
1 file changed