Change some compute admin image client methods to return one value

agents, aggregates, hosts, hypervisors, services were modified and tests
updated.

Partially implements: blueprint clients-return-one-value

Change-Id: Ib633020d06ea864fd228203b06cb5e68d75f8e60
diff --git a/tempest/scenario/test_aggregates_basic_ops.py b/tempest/scenario/test_aggregates_basic_ops.py
index 75769ce..469ac4a 100644
--- a/tempest/scenario/test_aggregates_basic_ops.py
+++ b/tempest/scenario/test_aggregates_basic_ops.py
@@ -43,7 +43,7 @@
         return cls.admin_credentials()
 
     def _create_aggregate(self, **kwargs):
-        _, aggregate = self.aggregates_client.create_aggregate(**kwargs)
+        aggregate = self.aggregates_client.create_aggregate(**kwargs)
         self.addCleanup(self._delete_aggregate, aggregate)
         aggregate_name = kwargs['name']
         availability_zone = kwargs['availability_zone']
@@ -55,23 +55,23 @@
         self.aggregates_client.delete_aggregate(aggregate['id'])
 
     def _get_host_name(self):
-        _, hosts = self.hosts_client.list_hosts()
+        hosts = self.hosts_client.list_hosts()
         self.assertTrue(len(hosts) >= 1)
         computes = [x for x in hosts if x['service'] == 'compute']
         return computes[0]['host_name']
 
     def _add_host(self, aggregate_id, host):
-        _, aggregate = self.aggregates_client.add_host(aggregate_id, host)
+        aggregate = self.aggregates_client.add_host(aggregate_id, host)
         self.addCleanup(self._remove_host, aggregate['id'], host)
         self.assertIn(host, aggregate['hosts'])
 
     def _remove_host(self, aggregate_id, host):
-        _, aggregate = self.aggregates_client.remove_host(aggregate_id, host)
+        aggregate = self.aggregates_client.remove_host(aggregate_id, host)
         self.assertNotIn(host, aggregate['hosts'])
 
     def _check_aggregate_details(self, aggregate, aggregate_name, azone,
                                  hosts, metadata):
-        _, aggregate = self.aggregates_client.get_aggregate(aggregate['id'])
+        aggregate = self.aggregates_client.get_aggregate(aggregate['id'])
         self.assertEqual(aggregate_name, aggregate['name'])
         self.assertEqual(azone, aggregate['availability_zone'])
         self.assertEqual(hosts, aggregate['hosts'])
@@ -81,15 +81,15 @@
                              aggregate['metadata'][meta_key])
 
     def _set_aggregate_metadata(self, aggregate, meta):
-        _, aggregate = self.aggregates_client.set_metadata(aggregate['id'],
-                                                           meta)
+        aggregate = self.aggregates_client.set_metadata(aggregate['id'],
+                                                        meta)
 
         for key, value in meta.items():
             self.assertEqual(meta[key], aggregate['metadata'][key])
 
     def _update_aggregate(self, aggregate, aggregate_name,
                           availability_zone):
-        _, aggregate = self.aggregates_client.update_aggregate(
+        aggregate = self.aggregates_client.update_aggregate(
             aggregate['id'], name=aggregate_name,
             availability_zone=availability_zone)
         self.assertEqual(aggregate['name'], aggregate_name)