Add volume clone flag to clone tests

test_volumes_clone and test_volumes_clone_negative are cloning in
their tests, but don't have the volume clone tag in them for
disabling in Tempest. This patch adds the tag to both of these
tests.

Closes-Bug: 1615770

Change-Id: Iff0f1bd8996bb8aa982ee0f3373e7454221ae41e
diff --git a/tempest/api/volume/test_volumes_clone.py b/tempest/api/volume/test_volumes_clone.py
index f38a068..7529dc2 100644
--- a/tempest/api/volume/test_volumes_clone.py
+++ b/tempest/api/volume/test_volumes_clone.py
@@ -23,6 +23,12 @@
 
 class VolumesCloneTest(base.BaseVolumeTest):
 
+    @classmethod
+    def skip_checks(cls):
+        super(VolumesCloneTest, cls).skip_checks()
+        if not CONF.volume_feature_enabled.clone:
+            raise cls.skipException("Cinder volume clones are disabled")
+
     @test.idempotent_id('9adae371-a257-43a5-9555-dc7c88e66e0e')
     def test_create_from_volume(self):
         # Creates a volume from another volume passing a size different from
diff --git a/tempest/api/volume/test_volumes_clone_negative.py b/tempest/api/volume/test_volumes_clone_negative.py
index ee51e00..d1bedb4 100644
--- a/tempest/api/volume/test_volumes_clone_negative.py
+++ b/tempest/api/volume/test_volumes_clone_negative.py
@@ -24,6 +24,12 @@
 
 class VolumesCloneTest(base.BaseVolumeTest):
 
+    @classmethod
+    def skip_checks(cls):
+        super(VolumesCloneTest, cls).skip_checks()
+        if not CONF.volume_feature_enabled.clone:
+            raise cls.skipException("Cinder volume clones are disabled")
+
     @test.idempotent_id('9adae371-a257-43a5-459a-dc7c88e66e0e')
     def test_create_from_volume_decreasing_size(self):
         # Creates a volume from another volume passing a size different from