/usr/lib/python2.7/dist-packages/nova/rootwrap/network.py is in nova-network 2012.1.3+stable-20130423-e52e6912-0ubuntu1.4.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/python2.7/dist-packages/nova/rootwrap/../../../../../share/pyshared/nova/rootwrap/network.py