/etc/logrotate.d/nova-dhcpbridge is in nova-network 2012.1.3+stable-20130423-e52e6912-0ubuntu1.4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
| 1 2 3 4 | /var/log/nova/nova-dhcpbridge.log {
    daily
    missingok
}
 |