Replace deprecated assertItemsEqual

It has been provided by testtools to ease migration from python 2, but
was deprecated in 2.7.2[1] and will be removed in 2.8.0[2].

[1] https://github.com/testing-cabal/testtools/commit/e0d56b7ce65ae5b3d
[2] https://github.com/testing-cabal/testtools/commit/f01e86084e6a858d1

Change-Id: I989758500f9a74857866119d09d7e24cb30ddb95
diff --git a/ironic_tempest_plugin/tests/api/admin/test_shards.py b/ironic_tempest_plugin/tests/api/admin/test_shards.py
index 0638702..5a5e4ba 100644
--- a/ironic_tempest_plugin/tests/api/admin/test_shards.py
+++ b/ironic_tempest_plugin/tests/api/admin/test_shards.py
@@ -92,7 +92,7 @@
         _, fetched_nodes = self.client.list_nodes(shard=shard)
         fetched_node_ids = [node['uuid'] for node in fetched_nodes['nodes']]
 
-        self.assertItemsEqual(good_node_ids, fetched_node_ids)
+        self.assertCountEqual(good_node_ids, fetched_node_ids)
 
     @decorators.idempotent_id('6f1e241d-4386-4730-b9ff-28c6a3dcad31')
     def test_only_show_multiple_requested_shards(self):
@@ -108,7 +108,7 @@
             shard=','.join([shard, second_shard]))
         fetched_node_ids = [node['uuid'] for node in fetched_nodes['nodes']]
 
-        self.assertItemsEqual(good_node_ids, fetched_node_ids)
+        self.assertCountEqual(good_node_ids, fetched_node_ids)
         self.assertNotIn(self.bad_node_id, fetched_node_ids)
         self.assertNotIn(self.none_node_id, fetched_node_ids)
 
@@ -148,4 +148,4 @@
         _, fetched_shards = self.client.get_shards()
         fetched_shards = [shard['name'] for shard in fetched_shards['shards']]
 
-        self.assertItemsEqual(self.shards, fetched_shards)
+        self.assertCountEqual(self.shards, fetched_shards)