timeutils.utcnow() should be used throughout the code instead of datetime.datetime.utcnow()

[Roman Podoliaka]

timeutils.utcnow() should be used instead of direct calls to datetime.datetime.utcnow() to make it easy to override its return value in tests.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/36662

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/36662
Committed: http://github.com/openstack/nova/commit/2e83be17d101c1501795708a9acc4671dee9c02d
Submitter: Jenkins
Branch: master

commit 2e83be17d101c1501795708a9acc4671dee9c02d
Author: Roman Podolyaka <email address hidden>
Date: Thu Jul 11 11:52:52 2013 +0300

    Use timeutils.utcnow() throughout the code

    timeutils.utcnow() should be used instead of direct calls to
    datetime.datetime.utcnow() to make it easy to override its return
    value in tests.

    Add a hacking rule to prevent regressions.

    Fixes bug 1200141.

    Change-Id: I170dbd7c9093bd627e2a0d5984b7ad1bf105c8d5