non utf-8 encoded changelogs cannot be parsed with recent python-debian

[Vincent Ladeuil]

While locally testing mass-import I came across import failures with the
following traceback:

Traceback (most recent call last):
  File "/caviar3/vila-tests/pkgimport/scripts/bin/import-package", line 7, in <module>
    main()
  File "/caviar3/vila-tests/pkgimport/scripts/udd/scripts/import_package.py", line 1172, in main
    only_before=options.only_before))
  File "/caviar3/vila-tests/pkgimport/scripts/udd/scripts/import_package.py", line 1066, in _import_package
    possible_transports=possible_transports)
  File "/caviar3/vila-tests/pkgimport/scripts/udd/scripts/import_package.py", line 946, in handle_collisions
    if clean_collision(importp, suite, db, temp_dir, download_dir, name, updates_branch):
  File "/caviar3/vila-tests/pkgimport/scripts/udd/scripts/import_package.py", line 880, in clean_collision
    return check_same(importp, db, revid, name, updates_branch, temp_dir, download_dir)
  File "/caviar3/vila-tests/pkgimport/scripts/udd/scripts/import_package.py", line 847, in check_same
    importp, db, revid, name, updates_branch, temp_dir, download_dir)
  File "/home/vila/src/bzr/trunk/bzrlib/cleanup.py", line 131, in run
    self.cleanups, self.func, self, *args, **kwargs)
  File "/home/vila/src/bzr/trunk/bzrlib/cleanup.py", line 165, in _do_with_cleanups
    result = func(*args, **kwargs)
  File "/caviar3/vila-tests/pkgimport/scripts/udd/scripts/import_package.py", line 867, in _check_same
    pull_debian=False)
  File "/home/vila/.bazaar/plugins/builddeb/import_dsc.py", line 1215, in import_package
    cl = self.get_changelog_from_source(extractor.extracted_debianised)
  File "/home/vila/.bazaar/plugins/builddeb/import_dsc.py", line 1083, in get_changelog_from_source
    cl.parse_changelog(open(cl_filename).read(), strict=False)
  File "/usr/lib/python2.7/dist-packages/debian/changelog.py", line 271, in parse_changelog
    line = line.decode(encoding)
  File "/usr/lib/python2.7/encodings/utf_8.py", line 16, in decode
    return codecs.utf_8_decode(input, errors, True)
UnicodeDecodeError: 'utf8' codec can't decode byte 0xfc in position 31: invalid start byte

This happens with python-debian-0.1.20ubuntu2 in oneiric (which I use
locally) but not on jubany that uses 0.1.14ubuntu2.