Nova

WIP .. all nova controller code works on single node (single OC) for now.
I don't really like that we're asking an external entity whether something local works. nova-manage basically fetches the entire service list from mysql and sees if they're "alive" by checking how recently they reported in.  In other words, even if nova-scheduler didn't rely on mysql, a failure on the mysql side would make it appear that nova-scheduler is down.