pygrace version 0.4-5 failed to build in oneiric

pygrace version 0.4-5 failed to build in oneiric
Link to failed build: https://launchpad.net/ubuntu/+source/pygrace/0.4-5/+build/2562083

Details about the rebuild:
http://people.ubuntuwire.org/~wgrant/rebuild-ftbfs-test/test-rebuild-20110816-oneiric.html

Direct link to the build log: https://launchpad.net/ubuntu/+source/pygrace/0.4-5/+build/2562083/+files/buildlog_ubuntu-oneiric-i386.pygrace_0.4-5_FAILEDTOBUILD.txt.gz

This log snippet might be of interest, since it triggered the matcher 'Purging chroot-autobuild'.
Excerpt 701 lines into the build log:

   dh_gencontrol
dpkg-gencontrol: warning: Depends field of package python-pygrace: unknown substitution variable ${python:Depends}
   dh_md5sums
   dh_builddeb
Found files in /usr/lib/python2.7/site-packages (must be in dist-packages for python2.7).
debian/python-pygrace/usr/lib/python2.7/site-packages
debian/python-pygrace/usr/lib/python2.7/site-packages/pygrace
debian/python-pygrace/usr/lib/python2.7/site-packages/pygrace/grace_np.py
debian/python-pygrace/usr/lib/python2.7/site-packages/pygrace/__init__.py
debian/python-pygrace/usr/lib/python2.7/site-packages/pygrace/pygrace.py
debian/python-pygrace/usr/lib/python2.7/site-packages/pygrace/gracePlot.py
debian/python-pygrace/usr/lib/python2.7/site-packages/pygrace-0.4-py2.7.egg-info
dh_builddeb: dpkg-deb --build debian/python-pygrace .. returned exit code 1
make: *** [binary] Error 25
dpkg-buildpackage: error: /usr/bin/fakeroot debian/rules binary gave error exit status 2
******************************************************************************
Build finished at 20110611-1000
FAILED [dpkg-buildpackage died]
Purging chroot-autobuild/build/buildd/pygrace-0.4