Actually these two builds failed because 'git fetch' failed, not because they only contained chumped CLs.

15:05:43: INFO: Translating result <class 'chromite.lib.cros_build_lib.RunCommandError'>: return code: 128; command: git fetch -f https://chromium-review.googlesource.com/chromiumos/third_party/kernel refs/changes/76/688176/1 refs/changes/97/691197/2 refs/changes/34/692834/1 refs/changes/94/691194/2 refs/changes/96/691196/2 refs/changes/95/691195/2 refs/changes/38/692838/1
fatal: The remote end hung up upon initial contact
cmd=['git', 'fetch', '-f', u'https://chromium-review.googlesource.com/chromiumos/third_party/kernel', u'refs/changes/76/688176/1', u'refs/changes/97/691197/2', u'refs/changes/34/692834/1', u'refs/changes/94/691194/2', u'refs/changes/96/691196/2', u'refs/changes/95/691195/2', u'refs/changes/38/692838/1'], cwd=/b/c/cbuild/repository/src/third_party/kernel/v3.18
Traceback (most recent call last):
  File "/b/c/cbuild/repository/chromite/lib/parallel.py", line 602, in TaskRunner
    task(*x, **task_kwargs)
  File "/b/c/cbuild/repository/chromite/lib/parallel.py", line 800, in <lambda>
    fn = lambda idx, task_args: out_queue.put((idx, task(*task_args)))
  File "/b/c/cbuild/repository/chromite/cbuildbot/patch_series.py", line 138, in _FetchChangesForRepo
    git.RunGit(repo, cmd, print_cmd=True)
  File "/b/c/cbuild/repository/chromite/lib/git.py", line 820, in RunGit
    ['git'] + cmd, **kwargs)
  File "/b/c/cbuild/repository/chromite/lib/retry_util.py", line 243, in GenericRetry
    return _run()
  File "/b/c/cbuild/repository/chromite/lib/retry_util.py", line 176, in _Wrapper
    ret = func(*args, **kwargs)
  File "/b/c/cbuild/repository/chromite/lib/retry_util.py", line 242, in _run
    return functor(*args, **kwargs)
  File "/b/c/cbuild/repository/chromite/lib/cros_build_lib.py", line 653, in RunCommand
    raise RunCommandError(msg, cmd_result)
RunCommandError: return code: 128; command: git fetch -f https://chromium-review.googlesource.com/chromiumos/third_party/kernel refs/changes/76/688176/1 refs/changes/97/691197/2 refs/changes/34/692834/1 refs/changes/94/691194/2 refs/changes/96/691196/2 refs/changes/95/691195/2 refs/changes/38/692838/1
fatal: The remote end hung up upon initial contact