Comment 1 for bug 1659295

Easy way to figure out how to find what test does this:

$ chmod a-w .
$ tox -e py35

cinder.tests.unit.volume.drivers.test_vzstorage.VZStorageTestCase.test_delete_snapshot_ploop
--------------------------------------------------------------------------------------------

Captured traceback:
~~~~~~~~~~~~~~~~~~~
    b'Traceback (most recent call last):'
    b' File "/home/eharney/src/cinder-review3/cinder/tests/unit/volume/drivers/test_vzstorage.py", line 331, in test_delete_snapshot_ploop'
    b' self._vz_driver.delete_snapshot(self.snap)'
    b' File "/home/eharney/src/cinder-review3/cinder/volume/drivers/remotefs.py", line 132, in lvo_inner1'
    b' return lvo_inner2()'
    b' File "/home/eharney/src/cinder-review3/.tox/py35/lib/python3.5/site-packages/oslo_concurrency/lockutils.py", line 271, in inner'
    b' return f(*args, **kwargs)'
    b' File "/home/eharney/src/cinder-review3/cinder/volume/drivers/remotefs.py", line 131, in lvo_inner2'
    b' return f(inst, *args, **kwargs)'
    b' File "/home/eharney/src/cinder-review3/cinder/volume/drivers/vzstorage.py", line 659, in delete_snapshot'
    b' self._delete_snapshot_ploop(snapshot)'
    b' File "/home/eharney/src/cinder-review3/cinder/volume/drivers/vzstorage.py", line 583, in _delete_snapshot_ploop'
    b' self._write_info_file(info_path, snap_info)'
    b' File "/home/eharney/src/cinder-review3/cinder/volume/drivers/remotefs.py", line 685, in _write_info_file'
    b" with open(info_path, 'w') as f:"
    b'PermissionError: [Errno 13] Permission denied: "<MagicMock name=\'RemoteFsClient().get_mount_point().__iadd__()\' id=\'139723801234232\'>.info"'
    b''