ovs_lib: get_port_tag_dict race with port removal

http://logstash.openstack.org/#eyJzZWFyY2giOiJtZXNzYWdlOiBcIlVuYWJsZSB0byBleGVjdXRlIFwiIEFORCBtZXNzYWdlOiBcIi0tY29sdW1ucz1uYW1lLHRhZ1wiIEFORCBtZXNzYWdlOiBcIm92cy12c2N0bDogbm8gcm93XCIiLCJmaWVsZHMiOltdLCJvZmZzZXQiOjAsInRpbWVmcmFtZSI6Ijg2NDAwIiwiZ3JhcGhtb2RlIjoiY291bnQiLCJ0aW1lIjp7InVzZXJfaW50ZXJ2YWwiOjB9LCJzdGFtcCI6MTQyOTE1OTgwNzI3OX0=

http://logs.openstack.org/45/160245/42/check/check-tempest-dsvm-neutron-dvr/09be830/logs/screen-q-agt.txt.gz
2015-04-15 10:05:53.275 DEBUG neutron.agent.linux.utils [req-3c5b23d8-3c6f-4145-
bdc2-c21c106b4192 None None]
Command: ['ovs-vsctl', '--timeout=10', '--oneline', '--format=json', '--', 'list
-ports', 'br-int']
Exit code: 0
Stdin:
Stdout: patch-tun\nqr-5a91d525-f6\nqr-a84affc0-ff\nqvo34a97bc9-9a\nsg-1e0fedbc-a
9\nsg-29d238f1-d0\nsg-591a0885-ba\nsg-d27f8240-60\ntap2566d7d2-51\ntap3704a993-8
5\ntapd8d2b093-c5

Stderr: execute /opt/stack/new/neutron/neutron/agent/linux/utils.py:134
2015-04-15 10:05:53.275 DEBUG neutron.agent.linux.utils [req-3c5b23d8-3c6f-4145-
bdc2-c21c106b4192 None None] Running command (rootwrap daemon): ['ovs-vsctl', '-
-timeout=10', '--oneline', '--format=json', '--', '--columns=name,tag', 'list',
'Port', 'patch-tun', 'qr-5a91d525-f6', 'qr-a84affc0-ff', 'qvo34a97bc9-9a', 'sg-1
e0fedbc-a9', 'sg-29d238f1-d0', 'sg-591a0885-ba', 'sg-d27f8240-60', 'tap2566d7d2-
51', 'tap3704a993-85', 'tapd8d2b093-c5'] execute_rootwrap_daemon /opt/stack/new/
neutron/neutron/agent/linux/utils.py:100
2015-04-15 10:05:53.276 3624 DEBUG neutron.agent.linux.ovsdb_monitor [-] Output
received from ovsdb monitor: {"data":[["b3d74d22-a37d-4cdc-a85c-e14437a46cc8","d
elete","sg-591a0885-ba",75]],"headings":["row","action","name","ofport"]}
 _read_stdout /opt/stack/new/neutron/neutron/agent/linux/ovsdb_monitor.py:44
2015-04-15 10:05:53.280 DEBUG neutron.agent.linux.utils [req-3c5b23d8-3c6f-4145-
bdc2-c21c106b4192 None None]
Command: ['ovs-vsctl', '--timeout=10', '--oneline', '--format=json', '--', '--co
lumns=name,tag', 'list', 'Port', u'patch-tun', u'qr-5a91d525-f6', u'qr-a84affc0-
ff', u'qvo34a97bc9-9a', u'sg-1e0fedbc-a9', u'sg-29d238f1-d0', u'sg-591a0885-ba',
 u'sg-d27f8240-60', u'tap2566d7d2-51', u'tap3704a993-85', u'tapd8d2b093-c5']
Exit code: 1
Stdin:
Stdout:
Stderr: ovs-vsctl: no row "sg-591a0885-ba" in table Port
 execute /opt/stack/new/neutron/neutron/agent/linux/utils.py:134
2015-04-15 10:05:53.281 ERROR neutron.agent.ovsdb.impl_vsctl [req-3c5b23d8-3c6f-
4145-bdc2-c21c106b4192 None None] Unable to execute ['ovs-vsctl', '--timeout=10'
, '--oneline', '--format=json', '--', '--columns=name,tag', 'list', 'Port', u'pa
tch-tun', u'qr-5a91d525-f6', u'qr-a84affc0-ff', u'qvo34a97bc9-9a', u'sg-1e0fedbc
-a9', u'sg-29d238f1-d0', u'sg-591a0885-ba', u'sg-d27f8240-60', u'tap2566d7d2-51'
, u'tap3704a993-85', u'tapd8d2b093-c5'].
2015-04-15 10:05:53.281 3624 TRACE neutron.agent.ovsdb.impl_vsctl Traceback (mos
t recent call last):
2015-04-15 10:05:53.281 3624 TRACE neutron.agent.ovsdb.impl_vsctl File "/opt/s
tack/new/neutron/neutron/agent/ovsdb/impl_vsctl.py", line 63, in run_vsctl
2015-04-15 10:05:53.281 3624 TRACE neutron.agent.ovsdb.impl_vsctl log_fail_a
s_error=False).rstrip()
2015-04-15 10:05:53.281 3624 TRACE neutron.agent.ovsdb.impl_vsctl File "/opt/s
tack/new/neutron/neutron/agent/linux/utils.py", line 137, in execute
2015-04-15 10:05:53.281 3624 TRACE neutron.agent.ovsdb.impl_vsctl raise Runt
imeError(m)
2015-04-15 10:05:53.281 3624 TRACE neutron.agent.ovsdb.impl_vsctl RuntimeError:
2015-04-15 10:05:53.281 3624 TRACE neutron.agent.ovsdb.impl_vsctl Command: ['ovs
-vsctl', '--timeout=10', '--oneline', '--format=json', '--', '--columns=name,tag
', 'list', 'Port', u'patch-tun', u'qr-5a91d525-f6', u'qr-a84affc0-ff', u'qvo34a9
7bc9-9a', u'sg-1e0fedbc-a9', u'sg-29d238f1-d0', u'sg-591a0885-ba', u'sg-d27f8240
-60', u'tap2566d7d2-51', u'tap3704a993-85', u'tapd8d2b093-c5']