Nexus VXLAN gateway: VM with 2 interfaces to the same subnet delete issues

With Nexus VXLAN gateway, there are delete issues with the last VM that has 2 interfaces to the same subnet.

1. When one interface is deleted, all the VLAN/VNI mapping configurations are deleted at the Nexus switch.

2. When the last interface or the VM is deleted, traceback is logged in screen-q-svc.log.

2014-12-03 18:03:38.433 ERROR neutron.plugins.ml2.managers [req-dda788e5-759f-4caf-81f6-a31b43025ede demo f0fd7da7d2874c1590a0092aab9014c3] Mechanism driver 'cisco_nexus' failed in delete_port_postcommit
2014-12-03 18:03:38.433 TRACE neutron.plugins.ml2.managers Traceback (most recent call last):
2014-12-03 18:03:38.433 TRACE neutron.plugins.ml2.managers File "/opt/stack/neutron/neutron/plugins/ml2/managers.py", line 299, in _call_on_drivers
2014-12-03 18:03:38.433 TRACE neutron.plugins.ml2.managers getattr(driver.obj, method_name)(context)
2014-12-03 18:03:38.433 TRACE neutron.plugins.ml2.managers File "/opt/stack/neutron/neutron/plugins/ml2/drivers/cisco/nexus/mech_cisco_nexus.py", line 400, in delete_port_postcommit
2014-12-03 18:03:38.433 TRACE neutron.plugins.ml2.managers self._delete_nve_member) if vxlan_segment else 0
2014-12-03 18:03:38.433 TRACE neutron.plugins.ml2.managers File "/opt/stack/neutron/neutron/plugins/ml2/drivers/cisco/nexus/mech_cisco_nexus.py", line 325, in _port_action_vxlan
2014-12-03 18:03:38.433 TRACE neutron.plugins.ml2.managers func(vni, device_id, mcast_group, host_id)
2014-12-03 18:03:38.433 TRACE neutron.plugins.ml2.managers File "/opt/stack/neutron/neutron/plugins/ml2/drivers/cisco/nexus/mech_cisco_nexus.py", line 155, in _delete_nve_member
2014-12-03 18:03:38.433 TRACE neutron.plugins.ml2.managers vni)
2014-12-03 18:03:38.433 TRACE neutron.plugins.ml2.managers File "/opt/stack/neutron/neutron/plugins/ml2/drivers/cisco/nexus/nexus_network_driver.py", line 253, in delete_nve_member
2014-12-03 18:03:38.433 TRACE neutron.plugins.ml2.managers self._edit_config(nexus_host, config=confstr)
2014-12-03 18:03:38.433 TRACE neutron.plugins.ml2.managers File "/opt/stack/neutron/neutron/plugins/ml2/drivers/cisco/nexus/nexus_network_driver.py", line 80, in _edit_config
2014-12-03 18:03:38.433 TRACE neutron.plugins.ml2.managers raise cexc.NexusConfigFailed(config=config, exc=e)
2014-12-03 18:03:38.433 TRACE neutron.plugins.ml2.managers NexusConfigFailed: Failed to configure Nexus:
2014-12-03 18:03:38.433 TRACE neutron.plugins.ml2.managers <config xmlns:xc="urn:ietf:params:xml:ns:netconf:base:1.0">
2014-12-03 18:03:38.433 TRACE neutron.plugins.ml2.managers <configure>
2014-12-03 18:03:38.433 TRACE neutron.plugins.ml2.managers <__XML__MODE__exec_configure>
2014-12-03 18:03:38.433 TRACE neutron.plugins.ml2.managers <interface>
2014-12-03 18:03:38.433 TRACE neutron.plugins.ml2.managers <nve>nve1</nve>
2014-12-03 18:03:38.433 TRACE neutron.plugins.ml2.managers <__XML__MODE_if-nve>
2014-12-03 18:03:38.433 TRACE neutron.plugins.ml2.managers <member>no member vni 9000</member>
2014-12-03 18:03:38.433 TRACE neutron.plugins.ml2.managers </__XML__MODE_if-nve>
2014-12-03 18:03:38.433 TRACE neutron.plugins.ml2.managers </interface>
2014-12-03 18:03:38.433 TRACE neutron.plugins.ml2.managers
2014-12-03 18:03:38.433 TRACE neutron.plugins.ml2.managers </__XML__MODE__exec_configure>
2014-12-03 18:03:38.433 TRACE neutron.plugins.ml2.managers </configure>
2014-12-03 18:03:38.433 TRACE neutron.plugins.ml2.managers </config>
2014-12-03 18:03:38.433 TRACE neutron.plugins.ml2.managers . Reason: ERROR: VNI delete validation failed
2014-12-03 18:03:38.433 TRACE neutron.plugins.ml2.managers .
2014-12-03 18:03:38.433 TRACE neutron.plugins.ml2.managers
2014-12-03 18:03:38.435 ERROR neutron.plugins.ml2.plugin [req-dda788e5-759f-4caf-81f6-a31b43025ede demo f0fd7da7d2874c1590a0092aab9014c3] mechanism_manager.delete_port_postcommit failed for port da89ec67-e825-4a52-8dfa-6a2556624a9e