Merged in Havana: fixed ip listing for single hosts

Nova has supported listing the fixed ips for a single host for a while. Well, except for that time we broke it by removing the database call it used and not noticing. My change to fix that situation has just landed, so this should now work again. To list the fixed ips used on a host, do something like:

    nova-manage fixed list hostname

I will propose a backport to grizzly for this now.