OVS agent may report AttributeError if db_get_val fails in port_bound()

[Ihar Hrachyshka]

If db_get_val fails for some reason, it returns None, and then we get AttributeError when trying to call .update() on it.

> /var/log/neutron/openvswitch-agent.log-20151007:2015-10-07 11:28:38.589 27560 ERROR neutron.agent.ovsdb.impl_vsctl [req-f164f551-f0e9-4284-8e53-0ffd9591a21d - - - - -] Unable to execute ['ovs-vsctl', '--timeout=10', '--oneline', '--format=json', '--', '--columns=other_config', 'list', 'Port', u'tapb5c2c181-bb'].
> /var/log/neutron/openvswitch-agent.log-20151007:2015-10-07 11:28:38.589 27560 ERROR neutron.agent.ovsdb.impl_vsctl Traceback (most recent call last):
> /var/log/neutron/openvswitch-agent.log-20151007:2015-10-07 11:28:38.589 27560 ERROR neutron.agent.ovsdb.impl_vsctl File "/usr/lib/python2.7/site-packages/neutron/agent/ovsdb/impl_vsctl.py", line 63, in run_vsctl
> /var/log/neutron/openvswitch-agent.log-20151007:2015-10-07 11:28:38.589 27560 ERROR neutron.agent.ovsdb.impl_vsctl log_fail_as_error=False).rstrip()
> /var/log/neutron/openvswitch-agent.log-20151007:2015-10-07 11:28:38.589 27560 ERROR neutron.agent.ovsdb.impl_vsctl File "/usr/lib/python2.7/site-packages/neutron/agent/linux/utils.py", line 158, in execute
> /var/log/neutron/openvswitch-agent.log-20151007:2015-10-07 11:28:38.589 27560 ERROR neutron.agent.ovsdb.impl_vsctl raise RuntimeError(m)
> /var/log/neutron/openvswitch-agent.log-20151007:2015-10-07 11:28:38.589 27560 ERROR neutron.agent.ovsdb.impl_vsctl RuntimeError:
> /var/log/neutron/openvswitch-agent.log-20151007:2015-10-07 11:28:38.589 27560 ERROR neutron.agent.ovsdb.impl_vsctl Command: ['ovs-vsctl', '--timeout=10', '--oneline', '--format=json', '--', '--columns=other_config', 'list', 'Port', u'tapb5c2c181-bb']
> /var/log/neutron/openvswitch-agent.log-20151007:2015-10-07 11:28:38.589 27560 ERROR neutron.agent.ovsdb.impl_vsctl Exit code: 1
> /var/log/neutron/openvswitch-agent.log-20151007:2015-10-07 11:28:38.589 27560 ERROR neutron.agent.ovsdb.impl_vsctl
> /var/log/neutron/openvswitch-agent.log-20151007:2015-10-07 11:28:38.589 27560 ERROR neutron.agent.ovsdb.impl_vsctl
> /var/log/neutron/openvswitch-agent.log-20151007:2015-10-07 11:28:38.590 27560 ERROR neutron.plugins.ml2.drivers.openvswitch.agent.ovs_neutron_agent [req-f164f551-f0e9-4284-8e53-0ffd9591a21d - - - - -] Error while processing VIF ports
> /var/log/neutron/openvswitch-agent.log-20151007:2015-10-07 11:28:38.590 27560 ERROR neutron.plugins.ml2.drivers.openvswitch.agent.ovs_neutron_agent Traceback (most recent call last):
> /var/log/neutron/openvswitch-agent.log-20151007:2015-10-07 11:28:38.590 27560 ERROR neutron.plugins.ml2.drivers.openvswitch.agent.ovs_neutron_agent File "/usr/lib/python2.7/site-packages/neutron/plugins/ml2/drivers/openvswitch/agent/ovs_neutron_agent.py", line 1725, in rpc_loop
> /var/log/neutron/openvswitch-agent.log-20151007:2015-10-07 11:28:38.590 27560 ERROR neutron.plugins.ml2.drivers.openvswitch.agent.ovs_neutron_agent ovs_restarted)
> /var/log/neutron/openvswitch-agent.log-20151007:2015-10-07 11:28:38.590 27560 ERROR neutron.plugins.ml2.drivers.openvswitch.agent.ovs_neutron_agent File "/usr/lib/python2.7/site-packages/neutron/plugins/ml2/drivers/openvswitch/agent/ovs_neutron_agent.py", line 1451, in process_network_ports
> /var/log/neutron/openvswitch-agent.log-20151007:2015-10-07 11:28:38.590 27560 ERROR neutron.plugins.ml2.drivers.openvswitch.agent.ovs_neutron_agent devices_added_updated, ovs_restarted))
> /var/log/neutron/openvswitch-agent.log-20151007:2015-10-07 11:28:38.590 27560 ERROR neutron.plugins.ml2.drivers.openvswitch.agent.ovs_neutron_agent File "/usr/lib/python2.7/site-packages/neutron/plugins/ml2/drivers/openvswitch/agent/ovs_neutron_agent.py", line 1342, in treat_devices_added_or_updated
> /var/log/neutron/openvswitch-agent.log-20151007:2015-10-07 11:28:38.590 27560 ERROR neutron.plugins.ml2.drivers.openvswitch.agent.ovs_neutron_agent ovs_restarted)
> /var/log/neutron/openvswitch-agent.log-20151007:2015-10-07 11:28:38.590 27560 ERROR neutron.plugins.ml2.drivers.openvswitch.agent.ovs_neutron_agent File "/usr/lib/python2.7/site-packages/neutron/plugins/ml2/drivers/openvswitch/agent/ovs_neutron_agent.py", line 1238, in treat_vif_port
> /var/log/neutron/openvswitch-agent.log-20151007:2015-10-07 11:28:38.590 27560 ERROR neutron.plugins.ml2.drivers.openvswitch.agent.ovs_neutron_agent fixed_ips, device_owner, ovs_restarted)
> /var/log/neutron/openvswitch-agent.log-20151007:2015-10-07 11:28:38.590 27560 ERROR neutron.plugins.ml2.drivers.openvswitch.agent.ovs_neutron_agent File "/usr/lib/python2.7/site-packages/neutron/plugins/ml2/drivers/openvswitch/agent/ovs_neutron_agent.py", line 798, in port_bound
> /var/log/neutron/openvswitch-agent.log-20151007:2015-10-07 11:28:38.590 27560 ERROR neutron.plugins.ml2.drivers.openvswitch.agent.ovs_neutron_agent port_other_config.update(vlan_mapping)
> /var/log/neutron/openvswitch-agent.log-20151007:2015-10-07 11:28:38.590 27560 ERROR neutron.plugins.ml2.drivers.openvswitch.agent.ovs_neutron_agent AttributeError: 'NoneType' object has no attribute 'update'

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/232077

[OpenStack Infra (hudson-openstack)]

Change abandoned by Ihar Hrachyshka (<email address hidden>) on branch: master
Review: https://review.openstack.org/232077
Reason: Superseded by https://review.openstack.org/#/c/234989