Description of problem:

Scale down delete nova compute services fails...

+----+------------------+--------------------------+----------+---------+-------+----------------------------+-----------------+
| Id | Binary           | Host                     | Zone     | Status  | State | Updated_at                 | Disabled Reason |
+----+------------------+--------------------------+----------+---------+-------+----------------------------+-----------------+
| 6  | nova-conductor   | controller-0.localdomain | internal | enabled | up    | 2017-05-03T09:40:08.000000 | -               |
| 7  | nova-scheduler   | controller-0.localdomain | internal | enabled | up    | 2017-05-03T09:40:05.000000 | -               |
| 8  | nova-consoleauth | controller-0.localdomain | internal | enabled | up    | 2017-05-03T09:40:13.000000 | -               |
| 9  | nova-compute     | compute-0.localdomain    | nova     | enabled | down  | 2017-05-03T09:13:12.000000 | -               |
| 10 | nova-compute     | compute-1.localdomain    | nova     | enabled | up    | 2017-05-03T09:40:11.000000 | -               |
| 16 | nova-scheduler   | compute-1.localdomain    | internal | enabled | up    | 2017-05-03T09:40:11.000000 | -               |
| 17 | nova-scheduler   | compute-0.localdomain    | internal | enabled | down  | 2017-05-03T09:13:12.000000 | -               |
+----+------------------+--------------------------+----------+---------+-------+----------------------------+-----------------+


Compute-0 has been scaled down, yet in the service list the nova-compute, nova-scheduler still exist

Version-Release number of selected component (if applicable):
5.8.0.12-rc1

How reproducible:
100%

Steps to Reproduce:
1. 
2.
3.

1. Login to the Cloudforms UI	
2. Go to Compute --> Providers -> infrastructure
	
3. Click on Openstack Infrastructure provider virtual thumbnail	
4. Click on the node compute node that you wish to scale down
	
5. Go to configuration --> Toggle this host in maintenance mode	

6. Click on Relationships --> cloud/infrastructure Providers...
	
7. Click on the node compute node that you wish to scale down
	
8. Click on "Configuration" --> "Scale this Infrastructure Provider Down"	
9. Select the compute node you wish to scale down from the infrastructure provider
	
10. Click on Scale Down
	
11. Click on Relationships
	The number of active nodes should be decreased after scaling down the compute nodes
11. #source ~/overcloudrc; nova service-list
	The scaled down compute node service should be deleted


Actual results:

Nova services still exist, hasn't been deleted

Expected results:
delete all nova services post scale down, for the scaled down node

Additional info:
[----] I, [2017-05-03T05:12:16.556419 #15243:e5513c]  INFO -- : MIQ(MiqQueue#delivered) Message id: [12000000148657], State: [ok], Delivered in [0.044144693] seconds
[----] I, [2017-05-03T05:12:16.586882 #15188:e5513c]  INFO -- : MIQ(MiqGenericWorker::Runner#get_message_via_drb) Message id: [12000000148402], MiqWorker id: [12000000000001], Zone: [default
], Role: [], Server: [], Ident: [generic], Target id: [], Instance id: [12000000001688], Task id: [], Command: [ManageIQ::Providers::Openstack::InfraManager::OrchestrationStack.post_scaledow
n_task], Timeout: [600], Priority: [100], State: [dequeue], Deliver On: [2017-05-03 09:11:59 UTC], Data: [], Args: [[#<CloudService id: 12000000000318, ems_ref: "9", source: "compute", execu
table_name: "nova-compute", hostname: "compute-0.localdomain", status: "up", scheduling_disabled: false, scheduling_disabled_reason: nil, ems_id: 12000000000005, host_id: 12000000000003, sys
tem_service_id: 12000000000349, availability_zone_id: 12000000000001, created_at: "2017-05-03 09:07:15", updated_at: "2017-05-03 09:07:15">, #<CloudService id: 12000000000321, ems_ref: "17",
 source: "compute", executable_name: "nova-scheduler", hostname: "compute-0.localdomain", status: "up", scheduling_disabled: false, scheduling_disabled_reason: nil, ems_id: 12000000000005, h
ost_id: 12000000000003, system_service_id: nil, availability_zone_id: nil, created_at: "2017-05-03 09:07:15", updated_at: "2017-05-03 09:07:15">], 12000000008803], Dequeued in: [109.39321757
5] seconds
[----] I, [2017-05-03T05:12:16.587025 #15188:e5513c]  INFO -- : MIQ(MiqQueue#deliver) Message id: [12000000148402], Delivering...
[----] I, [2017-05-03T05:12:16.602250 #15243:e5513c]  INFO -- : MIQ(MiqEventHandler::Runner#get_message_via_drb) Message id: [12000000148658], MiqWorker id: [12000000000006], Zone: [default]
, Role: [event], Server: [], Ident: [ems], Target id: [12000000000009], Instance id: [], Task id: [], Command: [EmsEvent.add], Timeout: [600], Priority: [100], State: [dequeue], Deliver On: 
[], Data: [], Args: [{:event_type=>"orchestration.stack.update.start", :source=>"OPENSTACK", :message=>nil, :timestamp=>"2017-05-03T09:11:40.204631", :username=>nil, :full_data=>{:content=>{
"message_id"=>"ddb78dc4-727a-4644-a855-280da3372c9c", "event_type"=>"orchestration.stack.update.start", "timestamp"=>"2017-05-03T09:11:40.204631", "payload"=>{"project_id"=>"e16a828715264616
a4f1a044f2283a60", "request_id"=>"req-627f7f9a-08b0-4121-8f74-13131245e545", "resource_id"=>"39032cc2-646b-427d-9bb2-f9437dc07aa2", "service"=>"orchestration.undercloud-0.redhat.local", "ten
ant_id"=>"e16a828715264616a4f1a044f2283a60", "user_id"=>"368daff69814479da9fa2206558f318e"}}, :context=>{}, :user_id=>nil, :priority=>nil, :content_type=>nil}, :ems_id=>12000000000009}], Deq
ueued in: [14.90795375] seconds
[----] I, [2017-05-03T05:12:16.602407 #15243:e5513c]  INFO -- : MIQ(MiqQueue#deliver) Message id: [12000000148658], Delivering...
[----] I, [2017-05-03T05:12:16.620070 #15243:e5513c]  INFO -- : MIQ(EmsEventHelper#before_handle) Processing EMS event [orchestration.stack.update.start] chain_id [] on EMS [12000000000009].
..
[----] E, [2017-05-03T05:12:16.635811 #15188:e5513c] ERROR -- : MIQ(MiqQueue#deliver) Message id: [12000000148402], Error: [undefined method `status_ok?' for #<MiqTask:0x0000001a97daf0>
Did you mean?  status?
               status
               status=
               status_was]
[----] E, [2017-05-03T05:12:16.636501 #15188:e5513c] ERROR -- : [NoMethodError]: undefined method `status_ok?' for #<MiqTask:0x0000001a97daf0>
Did you mean?  status?
               status
               status=
               status_was  Method:[rescue in deliver]
[----] E, [2017-05-03T05:12:16.636673 #15188:e5513c] ERROR -- : /opt/rh/cfme-gemset/gems/activemodel-5.0.2/lib/active_model/attribute_methods.rb:433:in `method_missing'
/var/www/miq/vmdb/app/models/manageiq/providers/openstack/infra_manager/orchestration_stack.rb:73:in `post_scaledown_task'
/var/www/miq/vmdb/app/models/miq_queue.rb:347:in `block in deliver'
: