These are the "centos6" corollary to devstack-.* node labels, but
we're not likely to run DevStack on them. Avoid confusion by going
ahead and using the new platform naming pattern settled on in the
2015-03-31 Infra meeting.
http://eavesdrop.openstack.org/meetings/infra/2015/infra.2015-03-31-19.00.html
Also update the nodepool logging config to get it back in sync with
reality.
Change-Id: Ie629b6b8e8f2401e3769a7b2c54844d950d9fd60