Cannot create a network using FlatDHCPManager without a bridge interface

[Mark McLoughlin]

In my simple, single-host setup with Nova:

  https://fedoraproject.org/wiki/Getting_started_with_OpenStack_Nova

I can't create a network using FlatDHCPManager unless I specify a bridge interface:

  2011-09-08 16:52:46,508 CRITICAL nova [-] --bridge_interface is required to create a network.
  (nova): TRACE: Traceback (most recent call last):
  (nova): TRACE: File "/usr/bin/nova-manage", line 1565, in <module>
  (nova): TRACE: main()
  (nova): TRACE: File "/usr/bin/nova-manage", line 1553, in main
  (nova): TRACE: fn(*fn_args, **fn_kwargs)
  (nova): TRACE: File "/usr/bin/nova-manage", line 719, in create
  (nova): TRACE: raise exception.NetworkNotCreated(req='--bridge_interface')
  (nova): TRACE: NetworkNotCreated: --bridge_interface is required to create a network.

There's really no need for this restriction. The code works fine without it, e.g.

    def ensure_bridge(_self, bridge, interface, net_attrs=None):
       ....
        if interface:
            out, err = _execute('brctl', 'addif', bridge, interface,
                            check_exit_code=False, run_as_root=True)