Merge branch 'stable-2.5' into stable-2.6

* stable-2.5:
  Fix parallel build failures
  QA: Add default setting for tests

Conflicts:
        Makefile.am (expected, from the parallel build fixes)
        qa/qa_config.py (due to cherry-pick, ignored, simply checkout out with --ours)

Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>