Comment 0 for bug 1439476

The following exceptions were seen in the log after doing the following:

 - Installing MAAS with a fresh database
 - Importing boot images
 - Adding a chassis with 2 nodes
 - Attempting commissioning (which fails since the cluster is unmanaged)
 *** At this point, I think a network has automatically been created, and the two nodes have been added to it
 - Editing the cluster interface to provide dynamic and static ranges, and change it to DNS+DHCP managed

2015-04-01 19:04:17 [-] 127.0.0.1 - - [02/Apr/2015:02:04:16 +0000] "GET /MAAS/clusters/992334f5-f5f0-4e61-88e9-e372ae174b1e/interfaces/eth0/edit/ HTTP/1.1" 200 2804 "http://maas-trusty/MAAS/clusters/992334f5-f5f0-4e61-88e9-e372ae174b1e/edit/" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2272.104 Safari/537.36"
2015-04-01 19:04:29 [maas] WARNING: Failed to create Network when adding/editing cluster interface maas-eth0 with error [{'ip': [u'Network with this Ip already exists.'], 'name': [u'Network with this Name already exists.']}]. This is OK if it already exists.
2015-04-01 19:04:29 [HTTPChannel,3,127.0.0.1] 500 Error - /MAAS/clusters/992334f5-f5f0-4e61-88e9-e372ae174b1e/interfaces/eth0/edit/
        Traceback (most recent call last):
          File "/usr/lib/python2.7/dist-packages/twisted/web/wsgi.py", line 315, in run
            appIterator = self.application(self.environ, self.startResponse)
          File "/usr/lib/python2.7/dist-packages/django/core/handlers/wsgi.py", line 206, in __call__
            response = self.get_response(request)
          File "/usr/lib/python2.7/dist-packages/maasserver/utils/views.py", line 166, in get_response
            response = get_response(request)
          File "/usr/lib/python2.7/dist-packages/maasserver/utils/views.py", line 155, in get_response
            request, get_resolver(None), sys.exc_info())
        --- <exception caught here> ---
          File "/usr/lib/python2.7/dist-packages/maasserver/utils/views.py", line 140, in get_response
            return django_get_response(request)
          File "/usr/lib/python2.7/dist-packages/maasserver/utils/orm.py", line 331, in __exit__
            self.fire()
          File "/usr/lib/python2.7/dist-packages/provisioningserver/utils/twisted.py", line 151, in wrapper
            return func(*args, **kwargs)
          File "/usr/lib/python2.7/dist-packages/maasserver/utils/async.py", line 180, in fire
            self._fire_in_reactor(hook).wait()
          File "/usr/lib/python2.7/dist-packages/crochet/_eventloop.py", line 219, in wait
            result.raiseException()
          File "<string>", line 2, in raiseException