Add skip for tests test_signed_image_upload_*

Skip tests if barbican_intagration_enabled = False

Related-PROD: PRODX-5292
Change-Id: Ie4fcfc00b0152755e2c82dfd13c6b7e473242871
(cherry picked from commit 09d0f6ff10a83f44b9b999582a94a513ebbb89e8)
(cherry picked from commit bc4e1475c1bc0fd49149aae462afbadc955e895c)
(cherry picked from commit bf331747566c14e0a7b6170e8501500d439b7296)
(cherry picked from commit 698750c31d25c3a7fe7b15f96490ac7f4992f7b8)
(cherry picked from commit 3ab3da8b4a830ee7ca5137bf85856dc79d59c695)
diff --git a/barbican_tempest_plugin/tests/scenario/test_image_signing.py b/barbican_tempest_plugin/tests/scenario/test_image_signing.py
index 19d2a1f..c05cabb 100644
--- a/barbican_tempest_plugin/tests/scenario/test_image_signing.py
+++ b/barbican_tempest_plugin/tests/scenario/test_image_signing.py
@@ -11,9 +11,10 @@
 # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 # License for the specific language governing permissions and limitations
 # under the License.
-import testtools
 
 from oslo_log import log as logging
+import testtools
+
 from tempest.api.compute import base as compute_base
 from tempest.common import utils
 from tempest import config
@@ -40,6 +41,9 @@
 
     @decorators.idempotent_id('4343df3c-5553-40ea-8705-0cce73b297a9')
     @utils.services('compute', 'image')
+    @testtools.skipUnless(
+        CONF.compute_feature_enabled.barbican_integration_enabled,
+        'Barbican integration must be enabled.')
     def test_signed_image_upload_and_boot(self):
         """Test that Nova boots a signed image.
 
@@ -64,6 +68,9 @@
     @utils.services('compute', 'image')
     @testtools.skipUnless(CONF.image_signature_verification.enforced,
                           "Image signature verification is not enforced")
+    @testtools.skipUnless(
+        CONF.compute_feature_enabled.barbican_integration_enabled,
+        'Barbican integration must be enabled.')
     def test_signed_image_upload_boot_failure(self):
         """Test that Nova refuses to boot an incorrectly signed image.