This is happening on some arm boards. The error handler in crosperf misses some cases.

  Traceback (most recent call last):
    File "/tmp/elm-release/R62-9824.0.0/autotest_files/client/common_lib/test.py", line 806, in _call_test_function
      return func(*args, **dargs)
    File "/tmp/elm-release/R62-9824.0.0/autotest_files/client/common_lib/test.py", line 470, in execute
      dargs)
    File "/tmp/elm-release/R62-9824.0.0/autotest_files/client/common_lib/test.py", line 347, in _call_run_once_with_retry
      postprocess_profiled_run, args, dargs)
    File "/tmp/elm-release/R62-9824.0.0/autotest_files/client/common_lib/test.py", line 380, in _call_run_once
      self.run_once(*args, **dargs)
    File "/tmp/elm-release/R62-9824.0.0/autotest_files/server/site_tests/telemetry_Crosperf/telemetry_Crosperf.py", line 188, in run_once
      '\nstdout:%s\nstderr:%s', exit_code,
  UnboundLocalError: local variable 'exit_code' referenced before assignment