tempest test of test_aggregates.py is broken for XenServer

[Jianghua Wang]

Citrix XenServer CI has been in failure status due the following failed tests:

2016-06-12 14:19:08.708 | {1} tempest.api.compute.admin.test_aggregates.AggregatesAdminTestJSON.test_aggregate_add_host_create_server_with_az [0.316267s] ... FAILED
2016-06-12 14:19:08.715 | {1} tempest.api.compute.admin.test_aggregates.AggregatesAdminTestJSON.test_aggregate_add_host_get_details [0.239005s] ... FAILED
2016-06-12 14:19:08.722 | {1} tempest.api.compute.admin.test_aggregates.AggregatesAdminTestJSON.test_aggregate_add_host_list [0.246983s] ... FAILED
2016-06-12 14:19:08.729 | {1} tempest.api.compute.admin.test_aggregates.AggregatesAdminTestJSON.test_aggregate_add_remove_host [0.268097s] ... FAILED

By some investigation, I believe that's broken by this change:
https://review.openstack.org/#/c/316672/9/tempest/api/compute/admin/test_aggregates.py

We can see the "Citrix XenServer CI" voted -1 on this patch set:
http://dd6b71949550285df7dc-dda4e480e005aaa13ec303551d2d8155.r49.cf1.rackcdn.com/72/316672/9/17788/index.html

[Bob Ball (bob-ball)]

Bug in Tempest, not Nova. Fixed in https://review.openstack.org/#/c/328836/