test_open_unlink() is broken

[ligurio]

Traceback (most recent call last):                                                                                                                
  File "/home/sergeyb/sources/unreliablefs/tests/test_unreliablefs.py", line 223, in test_open_unlink                                             
    assert fh.read() == data1+data2                                                                                                               
OSError: [Errno 9] Bad file descriptor