https://luci-milo.appspot.com/buildbot/chromeos/bob-paladin/1549


https://pantheon.corp.google.com/storage/browser/chromeos-autotest-results/156575268-chromeos-test/chromeos4-row9-rack10-host22/?project=chromeos-bot


  Traceback (most recent call last):
    File "/usr/local/autotest/server/server_job.py", line 921, in group_func
      test.runtest(self, url, tag, args, dargs)
    File "/usr/local/autotest/server/test.py", line 302, in runtest
      *logging_args)
    File "/usr/local/autotest/client/common_lib/test.py", line 894, in runtest
      exec ('import %s' % modulename, local_namespace, global_namespace)
    File "<string>", line 1, in <module>
    File "/usr/local/autotest/server/site_tests/cheets_CTS_N/cheets_CTS_N.py", line 19, in <module>
      from autotest_lib.server.cros import tradefed_test
    File "/usr/local/autotest/server/cros/tradefed_test.py", line 25, in <module>
      import lockfile
  ImportError: No module named lockfile