[Checkins] [zopefoundation/transaction] f8d611: Add test for 'txn.user = None'.

[GitHub]

  Branch: refs/heads/restore-100-pct-coverage
  Home:   https://github.com/zopefoundation/transaction
  Commit: f8d611a2701db794f747ec636756abb88bb5a84e
      https://github.com/zopefoundation/transaction/commit/f8d611a2701db794f747ec636756abb88bb5a84e
  Author: Tres Seaver <tseaver at palladion.com>
  Date:   2017-03-16 (Thu, 16 Mar 2017)

  Changed paths:
    M transaction/_transaction.py
    M transaction/tests/test__transaction.py

  Log Message:
  -----------
  Add test for 'txn.user = None'.

Restores 100% coverage.