[System Tests] Wrong exception is raised if revert snapshot is failed on node syncing time

[Andrey Sledzinskiy]

See to the next logs:
Add compute node to cluster in simple mode ... 2014-07-27 07:29:09,177 - INFO environment.py:338 -- We have snapshot with such name ready_with_3_slaves
2014-07-27 07:29:20,439 - INFO environment.py:341 -- Starting snapshot reverting ....
2014-07-27 07:29:20,905 - INFO environment.py:344 -- Starting snapshot resuming ...
2014-07-27 07:29:20,921 - INFO environment.py:393 -- Sync time on revert for admin
2014-07-27 07:29:29,522 - INFO environment.py:390 -- Node time: ['Sun Jul 27 07:29:29 UTC 2014\n']
2014-07-27 07:29:29,533 - INFO environment.py:354 -- Sync time on revert for node slave-01
2014-07-27 07:37:29,876 - WARNING environment.py:360 -- Paramiko exception catched while trying to run ntpdate: HTTP Error 401: Unauthorized
2014-07-27 07:45:30,331 - ERROR decorators.py:63 -- Traceback (most recent call last):
  File "/home/jenkins/workspace/master_fuelmain.system_test.centos.thread_2/fuelweb_test/helpers/decorators.py", line 61, in wrapper
    "fail", func.__name__)
  File "/home/jenkins/workspace/master_fuelmain.system_test.centos.thread_2/fuelweb_test/helpers/decorators.py", line 157, in create_diagnostic_snapshot
    task = env.fuel_web.task_wait(env.fuel_web.client.generate_logs(), 60 * 5)
  File "/home/jenkins/workspace/master_fuelmain.system_test.centos.thread_2/fuelweb_test/__init__.py", line 48, in wrapped
    result = func(*args, **kwargs)
  File "/home/jenkins/workspace/master_fuelmain.system_test.centos.thread_2/fuelweb_test/helpers/decorators.py", line 76, in wrapped
    response = func(*args, **kwargs)
  File "/home/jenkins/workspace/master_fuelmain.system_test.centos.thread_2/fuelweb_test/models/nailgun_client.py", line 326, in generate_logs
    return self.client.put("/api/logs/package")
  File "/home/jenkins/workspace/master_fuelmain.system_test.centos.thread_2/fuelweb_test/helpers/http.py", line 51, in put
    return self._open(req)
  File "/home/jenkins/workspace/master_fuelmain.system_test.centos.thread_2/fuelweb_test/helpers/http.py", line 62, in _open
    return self.opener.open(req)
  File "/usr/lib/python2.7/urllib2.py", line 410, in open
    response = meth(req, response)
  File "/usr/lib/python2.7/urllib2.py", line 523, in http_response
    'http', request, response, code, msg, hdrs)
  File "/usr/lib/python2.7/urllib2.py", line 448, in error
    return self._call_chain(*args)
  File "/usr/lib/python2.7/urllib2.py", line 382, in _call_chain
    result = func(*args)
  File "/usr/lib/python2.7/urllib2.py", line 531, in http_error_default
    raise HTTPError(req.get_full_url(), code, msg, hdrs, fp)
HTTPError: HTTP Error 401: Unauthorized

Seems that some exception was catched during node time syncing, then log_snapshot_on_error was called and try to generate snapshot, catch 401 unauthorized and then 'Paramiko exception catched while trying to run ntpdate: HTTP Error 401: Unauthorized' .
Another exception was catched during time sycning but the last one was raised

[Andrey Sledzinskiy (asledzinskiy)]

Issue isn't actual now due to changes in sync_admin_node