Log ip Information on ssh failures in the minimum scenario

The minimum scenario frequently have ssh connectivity issues,
 both with neutron and nova-network. Logging the ip and iptables
state at the failure, can help in finding the root cause sooner.

Change-Id: I3205541f96810b5b88e7c5ac3000fe1a1294ec65
diff --git a/tempest/scenario/test_minimum_basic.py b/tempest/scenario/test_minimum_basic.py
index 5464790..f2ee3b4 100644
--- a/tempest/scenario/test_minimum_basic.py
+++ b/tempest/scenario/test_minimum_basic.py
@@ -13,6 +13,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from tempest.common import debug
 from tempest import config
 from tempest.openstack.common import log as logging
 from tempest.scenario import manager
@@ -96,6 +97,7 @@
         except Exception:
             LOG.exception('ssh to server failed')
             self._log_console_output()
+            debug.log_ip_ns()
             raise
 
     def check_partitions(self):