nova-network doesn't set promisc mode on bridge interface

When br100 is not manually configured and nova.conf (network related part) is configured as:

--flat_network_bridge=br100
--network_manager=nova.network.manager.FlatDHCPManager
--flat_interface=eth0
--public_interface=eth0
--flat_network_dhcp_start=192.168.99.2
--network_host=10.10.10.10
--fixed_range=192.168.99.0/24
--flat-injected

nova-network fails to set promisc mode for br100:

2012-02-10 07:41:34,398 DEBUG nova.utils [req-749b0e68-fe1f-4442-9771-3f0297716b40 None None] Running cmd (subprocess): sudo nova-rootwrap ip addr add 192.168.99.1/24 brd 192.168.99.255 dev br100 from (pid=928) execute /usr/lib/python2.7/dist-packages/nova/utils.py:208
2012-02-10 07:41:34,431 DEBUG nova.utils [req-749b0e68-fe1f-4442-9771-3f0297716b40 None None] Running cmd (subprocess): sudo nova-rootwrap ip addr add 10.10.10.10/16 brd 10.10.255.255 scope global dev br100 from (pid=928) execute /usr/lib/python2.7/dist-packages/nova/utils.py:208
2012-02-10 07:41:34,464 DEBUG nova.utils [req-749b0e68-fe1f-4442-9771-3f0297716b40 None None] Running cmd (subprocess): sudo nova-rootwrap route add default gw 10.10.0.1 from (pid=928) execute /usr/lib/python2.7/dist-packages/nova/utils.py:208
2012-02-10 07:41:34,574 DEBUG nova.utils [req-749b0e68-fe1f-4442-9771-3f0297716b40 None None] Attempting to grab semaphore "dnsmasq_start" for method "restart_dhcp"... from (pid=928) inner /usr/lib/python2.7/dist-packages/nova/utils.py:813

Looking at the code (nova/network/linux_net.py):

    if(FLAGS.public_interface == dev):
        _execute('ip', 'link', 'set',
                     'dev', dev, 'promisc', 'on', run_as_root=True)

it looks like this will never be true, since public_interface is eth0, and 'dev' is br100. On the other hand, this works fine:

    if(FLAGS.public_interface == FLAGS.flat_interface):
        _execute('ip', 'link', 'set',
                     'dev', dev, 'promisc', 'on', run_as_root=True)