Code review comment for lp:~bgh/nova/ubuntu

Looks like that depends on whether you install iputils-arping or arping .. for some reason on my oneiric machine iputils-arping got installed (/usr/bin/arping). On natty the arping package is installed (/usr/sbin/arping). Anyhow, I'll update the merge prop as we probably want to use the arping package anyways (as opposed to iputils-arping).