Ironic should use oslo.utils

[Roman Prykhodchenko]

Since oslo.utils was separated into a separate library we should switch to using it.

[Ghe Rivero (ghe.rivero)]

There is a review for that, but doesn't have a related bug. Will update the commit message to address this.

[Roman Prykhodchenko (romcheg)]

Thank you Ghe! I thought it's a good idea to have a bug for that change.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/110596
Committed: https://git.openstack.org/cgit/openstack/ironic/commit/?id=4723aec443f550feeebd09c4c66e7a26e04de596
Submitter: Jenkins
Branch: master

commit 4723aec443f550feeebd09c4c66e7a26e04de596
Author: Ghe Rivero <email address hidden>
Date: Wed Jul 30 10:09:36 2014 +0000

    Migration to oslo.utils library

    oslo.utils has been released with the modules excutils, importutils,
    strutils and timeutils.

    Changes done:
    - Use the new oslo.utils modules when possible (not updated in the
    nova.ironic driver and other oslo.incubator modules)
    - importutils.import_module now is importutils.try_import
    - Updated requirements.txt with the new library
    - strutils.to_bytes now is strutils.string_to_bytes

    Once the nova.ironic driver is migrated into nova tree, old references
    and libraries can be cleaned (Bug: #1350269)

    Closes-Bug: #1353540

    Change-Id: Ic0af04ebd07b23eb94df32a6abf0e490d597f32a