Add objects/utils.py copied from Ironic
Add objects/utils.py copied from Ironic

This is a straight copy of utils.py from Ironic to support versioned
objects.

Change-Id: I9cb9b491373fa46630fc06428b06a515cda037d8

eshijia/SUR,mjbrewer/testindex,eshijia/SUR,Tennyson53/SUR,LaynePeng/magnum,paulczar/magnum,ffantast/magnum,dimtruck/magnum,eshijia/magnum,hongbin/magnum,ArchiFleKs/magnum,LaynePeng/magnum,ramielrowe/magnum,hongbin/magnum,ArchiFleKs/magnum,ChengTiesheng/magnum,Alzon/SUR,ddepaoli3/magnum,paulczar/magnum,Tennyson53/SUR,ffantast/magnum,ddepaoli3/magnum,annegentle/magnum,sajuptpm/magnum,ramielrowe/magnum,Tennyson53/magnum,openstack/magnum,Alzon/SUR,openstack/magnum,jay-lau/magnum,ChengTiesheng/magnum,Tennyson53/magnum,sajuptpm/magnum,dimtruck/magnum,eshijia/magnum,annegentle/magnum,mjbrewer/testindex,mjbrewer/testindex