Use the more common os_ names for novaclient

Users are quite accustomed to using these names, so we'll use
them. Also we may eventually want to monitor more than just
Nova.

The old parameters are not kept and will not be utilized anymore.

Change-Id: I17b6cb765ce73478204a66ae7fa79f4fb0cda14c
Merge "Use the more common os_ names for novaclient"