tricky-chrome-pfq just failed on HWTest provision:
https://cros-goldeneye.corp.google.com/chromeos/healthmonitoring/buildDetails?buildbucketId=8931764557514556704

reason: Download and install failed from chromeos4-devserver2.cros.corp.google.com onto chromeos4-row2-rack3-host1: Failed to install device image using payload at http://100.115.219.130:8082/update/tricky-chrome-pfq/R72-11189.0.0-rc1 on chromeos4-row2-rack3-host1. : command execution error

Forcing an update by setting app_version to ForcedUpdate.
[1024/124227:INFO:update_engine_client.cc(513)] Initiating update check and install.
[1024/124227:INFO:update_engine_client.cc(542)] Waiting for update to complete.
[1024/124513:ERROR:update_engine_client.cc(233)] Update failed, current operation is UPDATE_STATUS_IDLE, last error code is ErrorCode::kError(1)

devserver2.cros.corp.google.com onto chromeos4-row2-rack3-host1: Failed to install device image using payload at http://100.115.219.130:8082/update/tricky-chrome-pfq/R72-11189.0.0-rc1 on chromeos4-row2-rack3-host1. : command execution error
  * Command: 
      /usr/bin/ssh -a -x  -o ControlPath=/tmp/_autotmp_98t2ptssh-master/socket
      -o Protocol=2 -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null
      -o BatchMode=yes -o ConnectTimeout=30 -o ServerAliveInterval=900 -o
      ServerAliveCountMax=3 -o ConnectionAttempts=4 -l root -p 22
      chromeos4-row2-rack3-host1 "export LIBC_FATAL_STDERR_=1; if type
      \"logger\" > /dev/null 2>&1; then logger -tag \"autotest\"
      \"server[stack::_run|_base_update_handler_no_retry|run] ->
      ssh_run(/usr/bin/update_engine_client --update
      --omaha_url=http://100.115.219.130:8082/update/tricky-chrome-
      pfq/R72-11189.0.0-rc1)\";fi; /usr/bin/update_engine_client --update
      --omaha_url=http://100.115.219.130:8082/update/tricky-chrome-
      pfq/R72-11189.0.0-rc1"
  Exit status: 1
  Duration: 166.434089184
  
  stderr:
  [1024/124227:INFO:update_engine_client.cc(511)] Forcing an update by setting app_version to ForcedUpdate.
  [1024/124227:INFO:update_engine_client.cc(513)] Initiating update check and install.
  [1024/124227:INFO:update_engine_client.cc(542)] Waiting for update to complete.
  [1024/124513:ERROR:update_engine_client.cc(233)] Update failed, current operation is UPDATE_STATUS_IDLE, last error code is ErrorCode::kError(1)
10/24 12:45:45.382 INFO |        server_job:0217| 	END FAIL	provision_AutoUpdate	provision_AutoUpdate	timestamp=1540410345	localtime=Oct 24 12:45:45	
10/24 12:45:45.382 ERROR|           control:0074| Provision failed due to Exception.
Traceback (most recent call last):
  File "/usr/local/autotest/results/hosts/chromeos4-row2-rack3-host1/3388248-provision/20182410123830/control.srv", line 53, in provision_machine
    provision.Provision)
  File "/usr/local/autotest/server/cros/provision.py", line 400, in run_special_task_actions
    task.run_task_actions(job, host, labels)
  File "/usr/local/autotest/server/cros/provision.py", line 173, in run_task_actions
    raise SpecialTaskActionException()
SpecialTaskActionException
10/24 12:45:45.383 INFO |        server_job:0217| END FAIL	----	provision	timestamp=1540410345	localtime=Oct 24 12:45:45	
10/24 12:45:45.383 ERROR|        server_job:0825| Exception escaped control file, job aborting:
Traceback (most recent call last):
  File "/usr/local/autotest/server/server_job.py", line 817, in run
    self._execute_code(server_control_file, namespace)
  File "/usr/local/autotest/server/server_job.py", line 1340, in _execute_code
    execfile(code_file, namespace, namespace)
  File "/usr/local/autotest/results/hosts/chromeos4-row2-rack3-host1/3388248-provision/20182410123830/control.srv", line 108, in <module>
    job.parallel_simple(provision_machine, machines)
  File "/usr/local/autotest/server/server_job.py", line 619, in parallel_simple
    log=log, timeout=timeout, return_results=return_results)
  File "/usr/local/autotest/server/subcommand.py", line 98, in parallel_simple
    function(arg)
  File "/usr/local/autotest/results/hosts/chromeos4-row2-rack3-host1/3388248-provision/20182410123830/control.srv", line 99, in provision_machine
    raise Exception('')