cliff 1.16-17.0 breaks neutron lbaas-loadbalancer-list when no load balancers are present

[Michael Johnson]

Using cliff 1.16.0 or 1.17.0 we get an exception when listing load balancers and there are no load balancers in the tenant.

stack@devstack:~$ neutron lbaas-loadbalancer-list

<keystone debug removed>

DEBUG: keystoneauth.session REQ: curl -g -i -X GET http://172.21.21.14:9696/v2.0/lbaas/loadbalancers.json -H "User-Agent: python-neutronclient" -H "Accept: application/json" -H "X-Auth-Token: {SHA1}<redacted>"
DEBUG: keystoneauth.session RESP: [200] Date: Fri, 19 Feb 2016 23:06:08 GMT Connection: keep-alive Content-Type: application/json; charset=UTF-8 Content-Length: 21 X-Openstack-Request-Id: req-125303b1-f191-4bfe-8ffa-32a69afd6d95
RESP BODY: {"loadbalancers": []}

ERROR: neutronclient.shell list index out of range
Traceback (most recent call last):
  File "/opt/stack/python-neutronclient/neutronclient/shell.py", line 823, in run_subcommand
    return run_command(cmd, cmd_parser, sub_argv)
  File "/opt/stack/python-neutronclient/neutronclient/shell.py", line 105, in run_command
    return cmd.run(known_args)
  File "/usr/local/lib/python2.7/dist-packages/cliff/display.py", line 88, in run
    self.produce_output(parsed_args, column_names, data)
  File "/usr/local/lib/python2.7/dist-packages/cliff/lister.py", line 51, in produce_output
    parsed_args,
  File "/usr/local/lib/python2.7/dist-packages/cliff/formatters/table.py", line 64, in emit_list
    stdout, x, int(parsed_args.max_width), min_width)
  File "/usr/local/lib/python2.7/dist-packages/cliff/formatters/table.py", line 148, in _assign_max_widths
    first_line = x.get_string().splitlines()[0]
IndexError: list index out of range
list index out of range

Previous behavior with cliff 1.15.0 installed we get blank lines.

stack@devstack:~$ neutron lbaas-loadbalancer-list