Code review comment for lp:~ewanmellor/nova/xenapi-concurrency-model

Code looks good to the degree that I understand what xenapi does.

Style fixes: only one line of whitespace between methods, please read HACKING

It also looks like you may have been a little overzealous in wrapping the description xenapi_poll_task_interval.

If you think deferredToThread is globally useful you may consider putting it in utils.

Other than those small things code looks awesome, a welcome upgrade.