Fix celery task for figshare
Fix celery task for figshare

Move and copy fail for the figshare provider since `__new__()` in
the `FigshareProvider` class does not accept extra arguments such
as `is_celery_task` which was recently added for celery tasks. The
fix is simply adding the missing `**kwargs`.

Here is the related commit: https://github.com/CenterForOpenScience/waterbutler/commit/345b2d8d76a0e7425321624ea50b84831290e366

felliott/waterbutler,CenterForOpenScience/waterbutler