Update RAID spec based on what was coded
Update RAID spec based on what was coded

This updates the generic RAID interface specification to
reflect what was actually coded. This includes:
- instead of a RAIDInterface.update_raid_info(), we have
  ironic.common.raid.update_raid_info()
- some method names were changed
- HTTP 400 (not 404) is returned for RAID requests to drivers
  that don't support RAID

Change-Id: I57051e32085d4bb77a981e4b078773df7c9f8fde

bcornec/ironic-specs,openstack/ironic-specs,NaohiroTamura/ironic-specs