fail in systest venv with 'neutronclient._i18n import'

[Dmitry Kaigarodеsev]

During run system tests (master branch) facing with the error:

+ python fuelweb_test/run_tests.py -q --nologcapture --with-xunit --group=review_fuel_client
Traceback (most recent call last):
  File "fuelweb_test/run_tests.py", line 168, in <module>
    import_tests()
  File "fuelweb_test/run_tests.py", line 45, in import_tests
    from tests import test_backup_restore # noqa
  File "/home/jenkins/workspace/systest/master/fuelweb_test/tests/test_backup_restore.py", line 21, in <module>
    from fuelweb_test.helpers import os_actions
  File "/home/jenkins/workspace/systest/master/fuelweb_test/helpers/os_actions.py", line 22, in <module>
    from fuelweb_test.helpers import common
  File "/home/jenkins/workspace/systest/master/fuelweb_test/helpers/common.py", line 28, in <module>
    import neutronclient.v2_0.client as neutronclient
  File "/home/jenkins/venv-nailgun-tests-2.9/local/lib/python2.7/site-packages/neutronclient/v2_0/client.py", line 26, in <module>
    from neutronclient._i18n import _
  File "/home/jenkins/venv-nailgun-tests-2.9/local/lib/python2.7/site-packages/neutronclient/_i18n.py", line 24, in <module>
    _C = _translators.contextual_form
AttributeError: 'TranslatorFactory' object has no attribute 'contextual_form'

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.openstack.org/267025

[OpenStack Infra (hudson-openstack)]

Change abandoned by Dmitry Kaigarodsev (<email address hidden>) on branch: master
Review: https://review.openstack.org/267025
Reason: already done in https://review.openstack.org/#/c/266880/