Replace fileutils with oslo_utils

[Tan Lin]

Olso team will move the fileutils code (and associated tests) into oslo.utils, so replace them by using oslo.utils

http://specs.openstack.org/openstack/oslo-specs/specs/liberty/graduate-fileutils.html

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/201397

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/201397
Committed: https://git.openstack.org/cgit/openstack/ironic/commit/?id=bb9a2fa8e4922dcd75cf5629dc81a923c0b6b1dd
Submitter: Jenkins
Branch: master

commit bb9a2fa8e4922dcd75cf5629dc81a923c0b6b1dd
Author: Sinval Vieira <email address hidden>
Date: Mon Jul 13 23:27:57 2015 -0300

    Replace common.fileutils with oslo_utils.fileutils

    Olso team will move the fileutils code (and associated tests) into
    oslo_utils, so this change replace them by using oslo_utils.fileutils.

    Change-Id: Icfce636304edfa6a076620f85ed3b1f232232d99
    Co-Authored-By: Andrey Brito <andrey@dsc.​ufcg.​edu.​br>
    Closes-Bug: #1473815