NameError in exception handler in sqlalchemy API layer

This occurs when fixed_ip_get_by_address is called using the sqlalchemy DB backend:

ERROR:root:Traceback (most recent call last):
  File "/home/emellor/openstack/nova/xenapi/nova/rpc.py", line 98, in fetch
    super(Consumer, self).fetch(no_ack, auto_ack, enable_callbacks)
  File "/usr/lib/pymodules/python2.6/carrot/messaging.py", line 308, in fetch
    self.receive(message.payload, message)
  File "/home/emellor/openstack/nova/xenapi/nova/exception.py", line 76, in _wrap
    return f(*args, **kw)
  File "/home/emellor/openstack/nova/xenapi/nova/rpc.py", line 171, in receive
    d = defer.maybeDeferred(node_func, **node_args)
--- <exception caught here> ---
  File "/usr/lib/python2.6/dist-packages/twisted/internet/defer.py", line 117, in maybeDeferred
    result = f(*args, **kw)
  File "/home/emellor/openstack/nova/xenapi/nova/network/manager.py", line 257, in setup_fixed_ip
    fixed_ip_ref = self.db.fixed_ip_get_by_address(context, address)
  File "/home/emellor/openstack/nova/xenapi/nova/db/api.py", line 214, in fixed_ip_get_by_address
    return IMPL.fixed_ip_get_by_address(context, address)
  File "/home/emellor/openstack/nova/xenapi/nova/db/sqlalchemy/api.py", line 351, in fixed_ip_get_by_address
    except exc.NoResultFound:
exceptions.NameError: global name 'exc' is not defined