This currently doesn't report failures.
Also restrict files tested to HEAD~1..HEAD
instead of HEAD~2..HEAD.
Change-Id: I4983db5594fc2746eb28ec87a74d5d0ba27c9aaf
This replicates the run_tests.sh -8 behavior, running
flake8 only on changes made in the last commit and
working tree.
Change-Id: Iebd5746c78e840225f0860843c77f4c638877c26