neutron tempest check failed due to neutron-debug "RTNETLINK answers: File exists" error

http://logs.openstack.org/50/204950/3/check/gate-tempest-dsvm-neutron-full/a579098/logs/devstacklog.txt.gz

2015-07-23 11:19:46.643 | + neutron-debug --os-tenant-name admin --os-username admin --os-password secretadmin probe-create --device-owner compute 24f15c79-75fa-4cf3-b2be-2d9dfd6a80ae
2015-07-23 11:19:49.567 | 2015-07-23 11:19:49.567 10994 WARNING oslo_config.cfg [-] Option "use_namespaces" from group "DEFAULT" is deprecated for removal. Its value may be silently ignored in the future.
2015-07-23 11:19:50.148 | ++ _get_net_id private
2015-07-23 11:19:50.149 | ++ neutron --os-tenant-name admin --os-username admin --os-password secretadmin net-list
2015-07-23 11:19:50.149 | ++ grep private
2015-07-23 11:19:50.149 | ++ awk '{print $2}'
2015-07-23 11:19:51.224 | + private_net_id=2abd5092-7c33-4f94-989a-e40402230e16
2015-07-23 11:19:51.225 | + neutron-debug --os-tenant-name admin --os-username admin --os-password secretadmin probe-create --device-owner compute 2abd5092-7c33-4f94-989a-e40402230e16
2015-07-23 11:19:53.674 | 2015-07-23 11:19:53.674 11120 WARNING oslo_config.cfg [-] Option "use_namespaces" from group "DEFAULT" is deprecated for removal. Its value may be silently ignored in the future.
2015-07-23 11:19:54.168 | 2015-07-23 11:19:54.168 11120 ERROR neutron.agent.linux.utils [-]
2015-07-23 11:19:54.169 | Command: ['ip', 'netns', 'exec', u'qprobe-a3b65685-6d97-4831-958e-590b2c6a4121', 'ip', '-6', 'addr', 'add', 'fd4b:a41b:a53d:0:f816:3eff:fe4a:e2b5/64', 'scope', 'global', 'dev', u'tapa3b65685-6d']
2015-07-23 11:19:54.169 | Exit code: 2
2015-07-23 11:19:54.169 | Stdin:
2015-07-23 11:19:54.169 | Stdout:
2015-07-23 11:19:54.169 | Stderr: RTNETLINK answers: File exists
2015-07-23 11:19:54.169 |
2015-07-23 11:19:54.169 | 2015-07-23 11:19:54.169 11120 ERROR neutronclient.shell [-]
2015-07-23 11:19:54.169 | Command: ['ip', 'netns', 'exec', u'qprobe-a3b65685-6d97-4831-958e-590b2c6a4121', 'ip', '-6', 'addr', 'add', 'fd4b:a41b:a53d:0:f816:3eff:fe4a:e2b5/64', 'scope', 'global', 'dev', u'tapa3b65685-6d']
2015-07-23 11:19:54.169 | Exit code: 2
2015-07-23 11:19:54.169 | Stdin:
2015-07-23 11:19:54.169 | Stdout:
2015-07-23 11:19:54.169 | Stderr: RTNETLINK answers: File exists
2015-07-23 11:19:54.169 |
2015-07-23 11:19:54.230 | + exit_trap

Logstash: http://logstash.openstack.org/#eyJzZWFyY2giOiJtZXNzYWdlOlwiUlRORVRMSU5LIGFuc3dlcnM6IEZpbGUgZXhpc3RzXCIgQU5EIGZpbGVuYW1lOlwibG9ncy9kZXZzdGFja2xvZy50eHRcIiIsImZpZWxkcyI6W10sIm9mZnNldCI6MCwidGltZWZyYW1lIjoiNjA0ODAwIiwiZ3JhcGhtb2RlIjoiY291bnQiLCJ0aW1lIjp7InVzZXJfaW50ZXJ2YWwiOjB9LCJzdGFtcCI6MTQzNzY1MzMxNzQ2NCwibW9kZSI6IiIsImFuYWx5emVfZmllbGQiOiIifQ==