Please recognize field gpgsig in git automatic import

I'd like to have an automatic import of Coq v8.6 and Coq trunk (https://code.launchpad.net/~jgross-h/coq/v8.6, https://code.launchpad.net/~jgross-h/coq/trunk). However, these fail with a log like:

2016-07-15 03:05:29 INFO Starting job.
2016-07-15 03:05:29 INFO Getting exising bzr branch from central store.
2016-07-15 03:05:29 INFO [chan bzr SocketAsChannelAdapter] Opened sftp connection (server version 3)
2016-07-15 03:05:29 INFO [chan bzr SocketAsChannelAdapter] Opened sftp connection (server version 3)
2016-07-15 03:05:29 INFO 279 bytes transferred
2016-07-15 03:05:30 INFO Importing branch.
2016-07-15 03:05:32 INFO Counting objects: 165620, done. 0
2016-07-15 03:06:32 INFO 50309846 bytes transferred | Compressing objects 95/95
2016-07-15 03:06:55 INFO finding revisions to fetch:generating index 0/165620
2016-07-15 03:07:19 INFO finding revisions to fetch:generating index 0/165620
2016-07-15 03:07:36 INFO finding revisions to fetch 1/95
2016-07-15 03:07:40 INFO
Traceback (most recent call last):
  File "/srv/importd.launchpad.net/production/launchpad-rev-18115/scripts/code-import-worker.py", line 96, in <module>
    sys.exit(script.main())
  File "/srv/importd.launchpad.net/production/launchpad-rev-18115/scripts/code-import-worker.py", line 91, in main
    return import_worker.run()
  File "/srv/importd.launchpad.net/production/launchpad-rev-18115/lib/lp/codehosting/codeimport/worker.py", line 583, in run
    return self._doImport()
  File "/srv/importd.launchpad.net/production/launchpad-rev-18115/lib/lp/codehosting/codeimport/worker.py", line 737, in _doImport
    inter_branch.fetch(limit=revision_limit)
  File "/srv/importd.launchpad.net/production/launchpad-rev-18115/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-18115/bzrplugins/git/branch.py", line 745, in fetch_objects
    determine_wants, self.source.mapping, limit=limit)
  File "/srv/importd.launchpad.net/production/launchpad-rev-18115/bzrplugins/git/fetch.py", line 718, in fetch_objects
    limit)
  File "/srv/importd.launchpad.net/production/launchpad-rev-18115/bzrplugins/git/fetch.py", line 484, in import_git_objects
    mapping.revision_id_foreign_to_bzr)
  File "/srv/importd.launchpad.net/production/launchpad-rev-18115/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 a10e3e0252560992128f490dfcb3d76c4bbf317b>: ['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.

I'd be fine with the import stripping the gpgsig field from the commits, and I'd also be fine with it handling it correctly, but either way, I'd like the import to work.

Thanks.