ServerGroup object delete fails because it does not pass it's id to ServerGroupsManager object

If you create a ServerGroup object, and then try to call its delete() method, it will fail with the following:

Error
Traceback (most recent call last):
  File "/home/stoner/Projects/fog/fog/tests/numa.py", line 316, in tearDown
    self.cleanup()
  File "/home/stoner/Projects/fog/fog/tests/numa.py", line 303, in cleanup
    group.delete()
  File "/usr/lib/python2.7/site-packages/novaclient/v1_1/server_groups.py", line 33, in delete
    self.manager.delete(self)
  File "/usr/lib/python2.7/site-packages/novaclient/v1_1/server_groups.py", line 63, in delete
    self._delete('/os-server-groups/%s' % id)
  File "/usr/lib/python2.7/site-packages/novaclient/base.py", line 109, in _delete
    _resp, _body = self.api.client.delete(url)
  File "/usr/lib/python2.7/site-packages/novaclient/client.py", line 496, in delete
    return self._cs_request(url, 'DELETE', **kwargs)
  File "/usr/lib/python2.7/site-packages/novaclient/client.py", line 465, in _cs_request
    resp, body = self._time_request(url, method, **kwargs)
  File "/usr/lib/python2.7/site-packages/novaclient/client.py", line 439, in _time_request
    resp, body = self.request(url, method, **kwargs)
  File "/usr/lib/python2.7/site-packages/novaclient/client.py", line 433, in request
    raise exceptions.from_response(resp, body, url, method)
NotFound: Instance group <ServerGroup: ce418f29-ab80-4708-940f-997a3ce52eea> could not be found. (HTTP 404) (Request-ID: req-f47f61ee-6e39-45b0-b48e-ef24bf35218e)

This is because it is not passing it's id to the ServerGroupsManager object which requires the id to look up the instance.

This is occurring on python-novaclient version python-novaclient-2.20.0-1.fc22.noarch running on Fedora 20 openstack juno.