Bug#650197: Piuparts test of python-gi doesn't uninstall python-gi

[Dave Steele]

Package: python-gi
Version: 3.0.2-4
User: debian-qa at lists.debian.org
Usertags: piuparts piuparts.d.o

python-gi is failing piuparts with a large number of leftover owned
and unowned files after a purge.

    http://piuparts.debian.org/sid/fail/python-gi_3.0.2-4.log

   ...
   0m30.6s ERROR: FAIL: Package purging left files on system:
     /usr/lib/libpyglib-gi-2.0-python2.6.so	 owned by: python-gi
     /usr/lib/libpyglib-gi-2.0-python2.6.so.0	 owned by: python-gi
     /usr/lib/libpyglib-gi-2.0-python2.6.so.0.0.0	 owned by: python-gi
     /usr/lib/libpyglib-gi-2.0-python2.7.so	 owned by: python-gi
     /usr/lib/libpyglib-gi-2.0-python2.7.so.0	 owned by: python-gi
     /usr/lib/libpyglib-gi-2.0-python2.7.so.0.0.0	 owned by: python-gi
     /usr/lib/pyshared	 owned by: python-gi
     /usr/lib/pyshared/python2.6	 owned by: python-gi
     /usr/lib/pyshared/python2.6/gi	 owned by: python-gi
     /usr/lib/pyshared/python2.6/gi/_gi.so	 owned by: python-gi
     /usr/lib/pyshared/python2.6/gi/_glib	 owned by: python-gi
   ...

However, the Piuparts log on piuparts.debian.org does not indicate
that python-gi was uninstalled before the leftover file check.

A local test of the package, on sid, shows it as passing all tests,
with or without the '-a' option.

Why is piuparts skipping the uninstall of python-gi?