openvswitch-agent down when ovs-vsctl list-port fails

Exception handling for command execution failure looks missing especially for rpc support.
Agent looks easily down.

2012-08-17 04:59:43 DEBUG [quantum.agent.linux.utils]
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'list-ports', 'br-int']
Exit code: 142
Stdout: ''
Stderr: ''
Traceback (most recent call last):
  File "/opt/stack/quantum/quantum/plugins/openvswitch/agent/ovs_quantum_agent.py", line 864, in <module>
    main()
  File "/opt/stack/quantum/quantum/plugins/openvswitch/agent/ovs_quantum_agent.py", line 836, in main
    enable_tunneling = cfg.CONF.OVS.enable_tunneling
  File "/opt/stack/quantum/quantum/plugins/openvswitch/agent/ovs_quantum_agent.py", line 387, in daemon_loop
    self.rpc_loop()
  File "/opt/stack/quantum/quantum/plugins/openvswitch/agent/ovs_quantum_agent.py", line 368, in rpc_loop
    port_info = self.update_ports(ports)
  File "/opt/stack/quantum/quantum/plugins/openvswitch/agent/ovs_quantum_agent.py", line 296, in update_ports
    ports = self.int_br.get_vif_port_set()
  File "/opt/stack/quantum/quantum/agent/linux/ovs_lib.py", line 211, in get_vif_port_set
    port_names = self.get_port_name_list()
  File "/opt/stack/quantum/quantum/agent/linux/ovs_lib.py", line 175, in get_port_name_list
    res = self.run_vsctl(["list-ports", self.br_name])
  File "/opt/stack/quantum/quantum/agent/linux/ovs_lib.py", line 53, in run_vsctl
    return utils.execute(full_args, root_helper=self.root_helper)
  File "/opt/stack/quantum/quantum/agent/linux/utils.py", line 55, in execute
    raise RuntimeError(m)
RuntimeError:
Command: ['sudo', 'ovs-vsctl', '--timeout=2', 'list-ports', 'br-int']
Exit code: 142
Stdout: ''
Stderr: ''
DEBUG:amqplib:Closed channel #1
2012-08-17 04:59:43 DEBUG [amqplib] Closed channel #1