Fix variable attach_encrypted_volume if barbican is absent

Change-Id: I6aa65b154e35fd78ca6fa14d262fb4f612c629ce
Related-Prod: https://mirantis.jira.com/browse/PROD-19629
diff --git a/_modules/runtest/tempest_sections/compute_feature_enabled.py b/_modules/runtest/tempest_sections/compute_feature_enabled.py
index 3f53c01..193a40b 100644
--- a/_modules/runtest/tempest_sections/compute_feature_enabled.py
+++ b/_modules/runtest/tempest_sections/compute_feature_enabled.py
@@ -46,9 +46,11 @@
     def attach_encrypted_volume(self):
         compute_check = conditions.BaseRule('*.nova.compute.enabled', 'eq', True)
         cinder_check = conditions.BaseRule('*.cinder.controller.enabled', 'eq', True)
-        if compute_check.check(self.pillar) and cinder_check.check(self.pillar):
+        barbican_check = conditions.BaseRule('*.barbican.server.enabled', 'eq', True)
+        if compute_check.check(self.pillar) and cinder_check.check(self.pillar) and barbican_check.check(self.pillar):
             c = conditions.BaseRule('nova.controller.enabled', 'eq', True)
             return self.get_item_when_condition_match('nova.controller.barbican.enabled', c)
+        return False
 
     @property
     def block_migrate_cinder_iscsi(self):