Disable loadbalancers tests on pike

Fix disables two tests:
 * test_create_update_loadbalancer
 * test_add_delete_poolmember

Because this config when LBaasv2 and Octavia both
are enabled is not valid

Change-Id: Id54fd4c59280c00480788a9a4865772ea280717a
Related-PROD: PROD-24171
diff --git a/heat_tempest_plugin/tests/functional/test_lbaasv2.py b/heat_tempest_plugin/tests/functional/test_lbaasv2.py
index 3439179..3fd3a6b 100644
--- a/heat_tempest_plugin/tests/functional/test_lbaasv2.py
+++ b/heat_tempest_plugin/tests/functional/test_lbaasv2.py
@@ -87,8 +87,14 @@
 
     def setUp(self):
         super(LoadBalancerv2Test, self).setUp()
+        skip_msg = ''
         if not self.is_network_extension_supported('lbaasv2'):
-            self.skipTest('LBaasv2 extension not available, skipping')
+            skip_msg = 'LBaasv2 extension not available, skipping'
+        elif (self.is_network_extension_supported('lbaasv2') and
+              self.is_service_available('load-balancer')):
+            skip_msg = 'LBaasv2 and Octavia are both enabled, skipping'
+        if skip_msg:
+            self.skipTest(skip_msg)
 
     @decorators.idempotent_id('2f4a476c-cba7-448b-a7c1-85f7284f0293')
     def test_create_update_loadbalancer(self):