Use floating_ips_client from tempest-lib

The files below have been migrated to tempest-lib

 * floating_ips_client.py: Ide46dfbd437707c376bb44f86c99a87b739b9ef0
 * floating_ips.py: Iab0f7faca8d23d18061c5b3d13bb8b5e0536025c
 * test_floating_ips_client.py: Ide46dfbd437707c376bb44f86c99a87b739b9ef0

Now Tempest-lib provides those as stable interfaces. So Tempest should
start using those from lib and remove its own copy.

Change-Id: Ic7c87fa92737a7127fe0194633f8563ad4e61453
6 files changed