Quoting Julien Puydt <julien.puydt@laposte.net>:
Do you know pristine-tar is orphaned ? (bug #737871)
This is known to readers of this mailing list, e.g. https://lists.debian.org/debian-python/2014/10/msg00039.html So far, it just seems to work for (most of?) us. Cheers