Skip load balancer API test for ipv6 network

Default loadbalancer backend is haproxy version 1.4
which doesn't support ipv6. That leads to check-grenade-dvsm-neutron
job failures.

Need to skip this test until noop driver is used in tempest
configuration/API test or until backend supports ipv6

Change-Id: Ida4559752df827393845b1a78e562d69694d06ed
Closes-Bug: #1402007
diff --git a/tempest/api/network/test_load_balancer.py b/tempest/api/network/test_load_balancer.py
index 41294f6..4e777f6 100644
--- a/tempest/api/network/test_load_balancer.py
+++ b/tempest/api/network/test_load_balancer.py
@@ -422,5 +422,6 @@
         self.assertEqual(2, member['weight'])
 
 
+@test.skip_because(bug="1402007")
 class LoadBalancerIpV6TestJSON(LoadBalancerTestJSON):
     _ip_version = 6