Unable to configure DHCP due to IPAddress not assoicated with subnet

[Lee Trager]

maasserver.rack_controller: [critical] Failed configuring DHCP on rack controller 'id:4'.

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 434, in errback
    self._startRunCallbacks(fail)
  File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 501, in _startRunCallbacks
    self._runCallbacks()
  File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 588, in _runCallbacks
    current.result = callback(current.result, *args, **kw)
  File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 1184, in gotResult
    _inlineCallbacks(r, g, deferred)
--- <exception caught here> ---
  File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 1126, in _inlineCallbacks
    result = result.throwExceptionIntoGenerator(g)
  File "/usr/lib/python3/dist-packages/twisted/python/failure.py", line 389, in throwExceptionIntoGenerator
    return g.throw(self.type, self.value, self.tb)
  File "/usr/lib/python3/dist-packages/maasserver/dhcp.py", line 624, in configure_dhcp
    config = yield deferToDatabase(get_dhcp_configuration, rack_controller)
  File "/usr/lib/python3/dist-packages/twisted/python/threadpool.py", line 246, in inContext
    result = inContext.theWork()
  File "/usr/lib/python3/dist-packages/twisted/python/threadpool.py", line 262, in <lambda>
    inContext.theWork = lambda: context.call(ctx, func, *args, **kw)
  File "/usr/lib/python3/dist-packages/twisted/python/context.py", line 118, in callWithContext
    return self.currentContext().callWithContext(ctx, func, *args, **kw)
  File "/usr/lib/python3/dist-packages/twisted/python/context.py", line 81, in callWithContext
    return func(*args,**kw)
  File "/usr/lib/python3/dist-packages/provisioningserver/utils/twisted.py", line 875, in callInContext
    return func(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/provisioningserver/utils/twisted.py", line 232, in wrapper
    result = func(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/maasserver/utils/orm.py", line 686, in call_within_transaction
    return func_outside_txn(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/maasserver/utils/orm.py", line 504, in retrier
    return func(*args, **kwargs)
  File "/usr/lib/python3.5/contextlib.py", line 30, in inner
    return func(*args, **kwds)
  File "/usr/lib/python3/dist-packages/maasserver/dhcp.py", line 560, in get_dhcp_configuration
    default_domain, dhcp_snippets)
  File "/usr/lib/python3/dist-packages/maasserver/dhcp.py", line 466, in get_dhcp_configure_for
    vlan, rack_controller)
  File "/usr/lib/python3/dist-packages/maasserver/dhcp.py", line 430, in make_failover_peer_config
    rack_controller, vlan)
  File "/usr/lib/python3/dist-packages/maasserver/dhcp.py", line 236, in get_ip_address_for_rack_controller
    if ip_is_on_vlan(ip_address, vlan):
  File "/usr/lib/python3/dist-packages/maasserver/dhcp.py", line 213, in ip_is_on_vlan
    ip_address.subnet.vlan_id == vlan.id and
builtins.AttributeError: 'NoneType' object has no attribute 'vlan_id'