Skip test_subnet_details for baremetal

This test relies on network isolation for creating subnets with custom
DNS servers.  Baremetal relies on a pre-created shared network and this
will not pass currently.

Change-Id: I2c07a7f95a04d8e2dd7bb4485fb1a1dd13c54d65
diff --git a/tempest/scenario/test_network_basic_ops.py b/tempest/scenario/test_network_basic_ops.py
index f29fecf..4199b2c 100644
--- a/tempest/scenario/test_network_basic_ops.py
+++ b/tempest/scenario/test_network_basic_ops.py
@@ -435,13 +435,15 @@
             "admin_state_up of router to True")
 
     @test.idempotent_id('d8bb918e-e2df-48b2-97cd-b73c95450980')
+    @testtools.skipIf(CONF.baremetal.driver_enabled,
+                      'network isolation not available for baremetal nodes')
     @testtools.skipUnless(CONF.scenario.dhcp_client,
                           "DHCP client is not available.")
     @test.attr(type='smoke')
     @test.services('compute', 'network')
     def test_subnet_details(self):
         """Tests that subnet's extra configuration details are affecting
-        the VMs
+        the VMs. This test relies on non-shared, isolated tenant networks.
 
          NOTE: Neutron subnets push data to servers via dhcp-agent, so any
          update in subnet requires server to actively renew its DHCP lease.