Don't Log WARN if v3 API is disabled

[Dan Prince]

Using the latest Nova Havana code I now get the following warning message when the v3 API is disabled:

2013-06-03 21:58:14.647 31748 WARNING nova.api.openstack [-] V3 API has been disabled by configuration

Since this API is disabled by default we should probably just use LOG.info instead.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/31594

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/31594
Committed: http://github.com/openstack/nova/commit/3eaa34061a7aedf12e4b6b415a700b9d7f33d101
Submitter: Jenkins
Branch: master

commit 3eaa34061a7aedf12e4b6b415a700b9d7f33d101
Author: Dan Prince <email address hidden>
Date: Mon Jun 3 22:22:54 2013 -0400

    Don't log warn if v3 API is disabled.

    This makes sense because the V3 API is disabled by default.

    Fixes LP Bug #1187217.

    Change-Id: I1f182fa480bfef19dbe6d4b575200100fe2ee515