Consider this repair task:
    http://cautotest/tko/retrieve_logs.cgi?job=/results/hosts/chromeos2-row4-rack1-host4/343595-repair/

The status.log file shows this failure:
	START	----	repair.servoreset	timestamp=1503070109	localtime=Aug 18 08:28:29	
		FAIL	----	repair.servoreset	timestamp=1503070134	localtime=Aug 18 08:28:54	__init__() takes exactly 3 arguments (2 given)
	END FAIL	----	repair.servoreset	timestamp=1503070134	localtime=Aug 18 08:28:54	


That message can be traced to this exception from debug/autoserv.DEBUG:
08/18 08:28:54.343 DEBUG|      abstract_ssh:0470| send_file. source: /usr/local/autotest/client/bin/result_tools, dest: /usr/local/autotest, delete_dest: False,preserve_symlinks:False
08/18 08:28:54.353 DEBUG|          ssh_host:0296| Running (ssh) 'rsync --version' from 'send_file|use_rsync|check_rsync|run|wrapper|run_very_slowly'
08/18 08:28:54.473 WARNI|      abstract_ssh:0132| rsync not available on remote host chromeos2-row4-rack1-host4 -- disabled
08/18 08:28:54.473 DEBUG|      abstract_ssh:0499| Trying scp.
08/18 08:28:54.474 ERROR|            repair:0449| Repair failed: Reset the DUT via servo
Traceback (most recent call last):
  File "/usr/local/autotest/client/common_lib/hosts/repair.py", line 447, in _repair_host
    self.repair(host)
  File "/usr/local/autotest/server/hosts/cros_repair.py", line 402, in repair
    host.collect_logs('/var/log', local_log_dir, ignore_errors=True)
  File "/usr/local/autotest/server/hosts/abstract_ssh.py", line 848, in collect_logs
    result_tools_runner.run_on_client(self, remote_src_dir)
  File "/usr/local/autotest/client/bin/result_tools/runner.py", line 86, in run_on_client
    _deploy_result_tools(host)
  File "/usr/local/autotest/client/bin/result_tools/runner.py", line 60, in _deploy_result_tools
    excludes = _EXCLUDES)
  File "/usr/local/autotest/server/hosts/abstract_ssh.py", line 503, in send_file
    'excludes: %s' % excludes)
TypeError: __init__() takes exactly 3 arguments (2 given)

The exception is raised from this code in AbstractSSHHost.send_file:
        if try_scp:
            logging.debug('Trying scp.')
            if excludes:
                raise error.AutotestHostRunError(
                        '--exclude is not supported in scp, try to use rsync. '
                        'excludes: %s' % excludes)

It seems like there are several problems here that might need
fixing.  At minimum, the exception constructor needs to be
fixed to include the right number of arguments, so that the real
failure is properly reported.