/usr/lib/python2.7/dist-packages/maasserver/migrations/0025_remove_unused_fields_in_nodegroup.py is in python-django-maas 1.2+bzr1373+dfsg-0ubuntu1~12.04.6.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/python2.7/dist-packages/maasserver/migrations/../../../../../share/pyshared/maasserver/migrations/0025_remove_unused_fields_in_nodegroup.py