Revert baremetal v3 API extension

Baremetal is scheduled to be deprecated in Nova soon. Since
the V3 API is experimental in Havana, we should revert the
extension to avoid maintenance of the extension and its tests
for no real gain.

Things have changed enough since it was added that a simple
git-revert won't work. This reverts the following changes:

  5de5ae1b5d3763dbcf14bf3b4d43199ad5255adf
  92c9975bd2d53624ae595b895c2e96991ee43778
  2382186311794591fb4d35893ffa774157d6131b

Mailing list discussion:

http://lists.openstack.org/pipermail/openstack-dev/2013-September/014614.html

Change-Id: I3bdc7234f91eb4f9078ee24d7ab093b28f9930c9
Merge "Revert baremetal v3 API extension"