[Ironic] fix import of missing translation markers

[Vasyl Saienko]

Due to missing import of translation markers ironicclient failed.
It can land that nova mark instance build as ERROR.

https://paste.mirantis.net/show/1911/

[Vasyl Saienko (vsaienko)]

Marking as 'Won't Fix' for 9.0 It was fixed in Mitaka https://github.com/openstack/python-ironicclient/commit/eaa2456b895140b64a2b378b2d6ff802fe84986a

[Fuel Devops McRobotson (fuel-devops-robot)]

Fix proposed to branch: openstack-ci/fuel-8.0/liberty
Change author: Vasyl Saienko <email address hidden>
Review: https://review.fuel-infra.org/17567

[Vasyl Saienko (vsaienko)]

This issue is reproduced on scale when booting 50 Nova instances simultaneously with 100-150 active nova instances.

[Pavlo Shchelokovskyy (pshchelo)]

The error happens mostly when API is unresponsive and when ironicclient is used from some automation scripts/code, like rally.

to reproduce on MOS8:

1) deploy cluster with ironic
2) stop all ironic-api services on controllers to simulate non-responsive API
3) get Ironic API endpoint
   $ openstack catalog show baremetal
4) get Keystone token
   $ openstack token issue
5) issue following command
   $ ironic --ironic-url <public-ironic-endpoint-from-step-3> --os-auth-token <token-id-from-step-4> node-list

Expected:
meaningful HTTP-related error after some timeout

Actual:
almost immediate "global name '_' is not defined"

one can also prepend --debug to ironic command to see the actual request/response interchange