RHOSP13 VNX VolumesSnapshotTestJSON tearDownClass failed 'OSError: [Errno 18] Invalid cross-device link'

[Sam Wan]

ran tempest on RHOSP13 and VolumesSnapshotTestJSON teardownclass failed.
======
root@samctl0 test]# tempest run --regex VolumesSnapshotTestJSON
{0} tempest.api.volume.test_volumes_snapshots.VolumesSnapshotTestJSON.test_snapshot_backup [64.533081s] ... ok
{0} tempest.api.volume.test_volumes_snapshots.VolumesSnapshotTestJSON.test_snapshot_create_delete_with_volume_in_use [44.419093s] ... ok
{0} tempest.api.volume.test_volumes_snapshots.VolumesSnapshotTestJSON.test_snapshot_create_get_list_update_delete [4.616859s] ... ok
{0} tempest.api.volume.test_volumes_snapshots.VolumesSnapshotTestJSON.test_snapshot_create_offline_delete_online [44.189326s] ... ok
{0} tempest.api.volume.test_volumes_snapshots.VolumesSnapshotTestJSON.test_volume_from_snapshot [83.649180s] ... ok
{0} tearDownClass (tempest.api.volume.test_volumes_snapshots.VolumesSnapshotTestJSON) [0.000000s] ...
FAILED

Captured traceback:
~~~~~~~~~~~~~~~~~~~
    Traceback (most recent call last):
      File "/usr/lib/python2.7/site-packages/tempest/test.py", line 224, in tearDownClass
        six.reraise(etype, value, trace)
      File "/usr/lib/python2.7/site-packages/tempest/test.py", line 196, in tearDownClass
        teardown()
      File "/usr/lib/python2.7/site-packages/tempest/test.py", line 562, in resource_cleanup
        raise testtools.MultipleExceptions(*cleanup_errors)
    testtools.runtest.MultipleExceptions: (<class 'tempest.lib.exceptions.DeleteErrorException'>, Resource 9ea09b32-6189-4701-823d-1dd392c10f87 failed to delete and is in ERROR status, <traceback object at 0x7f4c712114d0>)
======

errors in cinder log
======
2018-09-21 01:56:51.396 31 ERROR oslo_messaging.rpc.server File "/usr/lib/python2.7/site-packages/cinder/volume/drivers/dell_emc/vnx/client.py", line 170, in delay_delete_lun
2018-09-21 01:56:51.396 31 ERROR oslo_messaging.rpc.server self.queue.put(self.vnx.delete_lun, name=name)
2018-09-21 01:56:51.396 31 ERROR oslo_messaging.rpc.server File "/usr/lib/python2.7/site-packages/storops/lib/tasks.py", line 47, in put
2018-09-21 01:56:51.396 31 ERROR oslo_messaging.rpc.server self._q.put_nowait(item)
2018-09-21 01:56:51.396 31 ERROR oslo_messaging.rpc.server File "/usr/lib/python2.7/site-packages/persistqueue/queue.py", line 124, in put_nowait
2018-09-21 01:56:51.396 31 ERROR oslo_messaging.rpc.server return self.put(item, False)
2018-09-21 01:56:51.396 31 ERROR oslo_messaging.rpc.server File "/usr/lib/python2.7/site-packages/persistqueue/queue.py", line 103, in put
2018-09-21 01:56:51.396 31 ERROR oslo_messaging.rpc.server self._put(item)
2018-09-21 01:56:51.396 31 ERROR oslo_messaging.rpc.server File "/usr/lib/python2.7/site-packages/persistqueue/queue.py", line 121, in _put
2018-09-21 01:56:51.396 31 ERROR oslo_messaging.rpc.server self._saveinfo()
2018-09-21 01:56:51.396 31 ERROR oslo_messaging.rpc.server File "/usr/lib/python2.7/site-packages/persistqueue/queue.py", line 216, in _saveinfo
2018-09-21 01:56:51.396 31 ERROR oslo_messaging.rpc.server os.rename(tmpfn, self._infopath())
2018-09-21 01:56:51.396 31 ERROR oslo_messaging.rpc.server OSError: [Errno 18] Invalid cross-device link
2018-09-21 01:56:51.396 31 ERROR oslo_messaging.rpc.server
======

This test case requires 'state_path=/tmp' set in cinder.conf