Comment 4 for bug 1554502

Increasing the timeout value doesn't cover all situations. By default, the Nova API won't return more than 1,000 items. This can be changed by using the osapi_max_limit configuration parameter but there's still a limit. So once we reach this limit, the collected metrics will be incorrect.

IMO, a more complete fix would be at least to:
- explicitly set the number of items that the plugin wants to get and make as many calls as necessary to get the whole data.
- keep a local cache and use the Changes-since parameter [1] to reduce the size and the number of the subsequent requests.

[1] http://docs.openstack.org/developer/nova/v2/polling_changes-since_parameter.html