vcs-import of audacity fails due to extra gpgsig field in git commit

The vcs-import of audacity fails:
https://code.launchpad.net/~audacity-team/audacity/master

Traceback (most recent call last):
  File "/srv/importd.launchpad.net/production/launchpad-rev-18298/scripts/code-import-worker.py", line 106, in <module>
    sys.exit(script.main())
  File "/srv/importd.launchpad.net/production/launchpad-rev-18298/scripts/code-import-worker.py", line 101, in main
    return import_worker.run()
  File "/srv/importd.launchpad.net/production/launchpad-rev-18298/lib/lp/codehosting/codeimport/worker.py", line 617, in run
    return self._doImport()
  File "/srv/importd.launchpad.net/production/launchpad-rev-18298/lib/lp/codehosting/codeimport/worker.py", line 820, in _doImport
    inter_branch.fetch(limit=revision_limit)
  File "/srv/importd.launchpad.net/production/launchpad-rev-18298/bzrplugins/git/branch.py", line 722, in fetch
    self.fetch_objects(stop_revision, fetch_tags=fetch_tags, limit=limit)
  File "/srv/importd.launchpad.net/production/launchpad-rev-18298/bzrplugins/git/branch.py", line 745, in fetch_objects
    determine_wants, self.source.mapping, limit=limit)
  File "/srv/importd.launchpad.net/production/launchpad-rev-18298/bzrplugins/git/fetch.py", line 718, in fetch_objects
    limit)
  File "/srv/importd.launchpad.net/production/launchpad-rev-18298/bzrplugins/git/fetch.py", line 484, in import_git_objects
    mapping.revision_id_foreign_to_bzr)
  File "/srv/importd.launchpad.net/production/launchpad-rev-18298/bzrplugins/git/mapping.py", line 334, in import_commit
    raise UnknownCommitExtra(commit, [item[0] for item in commit.extra])
bzrlib.plugins.git.errors.UnknownCommitExtra: Unknown extra fields in <Commit 4b4027ce1ff85f274048300d9877086ec87f8f93>: ['gpgsig'].
Import failed:
Traceback (most recent call last):
Failure: twisted.internet.error.ProcessTerminated: A process has ended with a probable error condition: process ended with exit code 1.