The MAC address used in this plugin isn't in the OUI list but appears to be common to Openstack, not just to HP Cloud. Notably Rackspace is moving to Openstack as well, so this wouldn't work very well.
If there was a reliable MAC prefix here, ideally we would upfactor this code rather than duplicating the EC2 code as well.
I suppose we could use this for detecting Openstack though, or something like it. That becomes an interesting problem; openstack can use different virtualization technology, which we would want to store in node[:virtualization] and could be used by different cloud providers which we use node[:cloud] for. Perhaps we need to expand one of the two. I propose node[:cloud][:system] to be 'openstack' to match node[:virtualization][:system].