Switch to decorators.idempotent_id

test.idempotent_id is being kept temporary to migrate
to new lib interface. Now idempotent_id is available as Tempest stable
interface decorators and all plugins tests using the old decorator
should be switched to new interface.

In future, Once all plugins are switched to new decorator Tempest
will remove the test.idempotent_id

Change-Id: Ie7789c072b8954de5821777bf3f672cdfa4bceca
Related-Bug: 1616913
diff --git a/cinder/tests/tempest/api/volume/test_volume_backup.py b/cinder/tests/tempest/api/volume/test_volume_backup.py
index 72c32ff..9e8d90f 100644
--- a/cinder/tests/tempest/api/volume/test_volume_backup.py
+++ b/cinder/tests/tempest/api/volume/test_volume_backup.py
@@ -20,7 +20,7 @@
 from tempest.common import waiters
 from tempest import config
 from tempest.lib.common.utils import data_utils
-from tempest import test
+from tempest.lib import decorators
 
 # TODO(obutenko): Remove this when liberty-eol happens.
 snapshot_backup_opt = cfg.BoolOpt('snapshot_backup',
@@ -42,7 +42,7 @@
 
     @testtools.skipUnless(CONF.volume_feature_enabled.snapshot_backup,
                           "Skip. Not implemented in Liberty.")
-    @test.idempotent_id('885410c6-cd1d-452c-a409-7c32b7e0be15')
+    @decorators.idempotent_id('885410c6-cd1d-452c-a409-7c32b7e0be15')
     def test_volume_snapshot_backup(self):
         """Create backup from snapshot."""
         volume = self.create_volume()
@@ -67,7 +67,7 @@
         self.volumes_client.delete_volume(volume['id'])
         self.volumes_client.wait_for_resource_deletion(volume['id'])
 
-    @test.idempotent_id('b5d837b0-7066-455d-88fc-4a721a899306')
+    @decorators.idempotent_id('b5d837b0-7066-455d-88fc-4a721a899306')
     def test_backup_create_and_restore_to_an_existing_volume(self):
         """Test backup create and restore to an existing volume."""
         # Create volume
@@ -94,7 +94,7 @@
         self.assertEqual(src_vol['id'], restore['volume_id'])
         self.assertEqual(backup['id'], restore['backup_id'])
 
-    @test.idempotent_id('c810fe2c-cb40-43ab-96aa-471b74516a98')
+    @decorators.idempotent_id('c810fe2c-cb40-43ab-96aa-471b74516a98')
     def test_incremental_backup(self):
         """Test create incremental backup."""
         # Create volume from image