cli ipgroup-list fails when ipgroup has no servers

[mmarano]

I had an ipgroup on rackspace with no servers in the group. Attempting to list the ipgroups failed until I deleted the ipgroup.

Traceback (most recent call last):
File "/Users/mmarano/ve/openstack/bin/openstack-compute", line 8, in
load_entry_point('openstack.compute==2.0a1', 'console_scripts', 'openstack-compute')()
File "/Users/mmarano/ve/openstack/src/openstack.compute/openstack/compute/shell.py", line 488, in main
ComputeShell().main(sys.argv[1:])
File "/Users/mmarano/ve/openstack/src/openstack.compute/openstack/compute/shell.py", line 144, in main
args.func(args)
File "/Users/mmarano/ve/openstack/src/openstack.compute/openstack/compute/shell.py", line 323, in do_ipgroup_list
formatters = {'Server List': pretty_server_list})
File "/Users/mmarano/ve/openstack/src/openstack.compute/openstack/compute/shell.py", line 473, in print_list
row.append(formattersfield)
File "/Users/mmarano/ve/openstack/src/openstack.compute/openstack/compute/shell.py", line 318, in pretty_server_list
if len(ipgroup.servers):
File "/Users/mmarano/ve/openstack/src/openstack.compute/openstack/compute/base.py", line 95, in getattr
raise AttributeError(k)
AttributeError: servers
(openstack)mmarano:compute m