OST failure on master in 'snapshot_merge' test

[Nadav Goldin]

Hi,
There is a new failure in master, on 'snapshot_merge' test(not live),
vdsm.log shows:

2016-12-13 09:57:30,399 ERROR (tasks/0) [storage.Image] delete() takes
exactly 4 arguments (3 given) (image:1321)
Traceback (most recent call last):
  File "/usr/share/vdsm/storage/image.py", line 1309, in merge
    sdDom, srcVolParams, volParams, reqSize, chain)
  File "/usr/share/vdsm/storage/image.py", line 1068, in _baseCowVolumeMerge
    tmpVol.delete(postZero=False, force=True)
TypeError: delete() takes exactly 4 arguments (3 given)
2016-12-13 09:57:30,401 ERROR (tasks/0) [storage.TaskManager.Task]
(Task='085bee3e-681f-4e3f-9b37-d9abbd6b2903') Unexpected error
(task:870)
Traceback (most recent call last):
  File "/usr/share/vdsm/storage/task.py", line 877, in _run
    return fn(*args, **kargs)
  File "/usr/share/vdsm/storage/task.py", line 333, in run
    return self.cmd(*self.argslist, **self.argsdict)
  File "/usr/lib/python2.7/site-packages/vdsm/storage/securable.py",
line 79, in wrapper
    return method(self, *args, **kwargs)
  File "/usr/share/vdsm/storage/sp.py", line 1837, in mergeSnapshots
    discard)
  File "/usr/share/vdsm/storage/image.py", line 1322, in merge
    raise se.SourceImageActionError(imgUUID, sdUUID, str(e))

This failure is from recent hours. The hosts and engine logs can be
found here[1]

Could someone take a look?

Thanks,

Nadav.

[1] http://jenkins.ovirt.org/job/test-repo_ovirt_experimental_master/4160/artifact/exported-artifacts/basic_suite_master.sh-el7/exported-artifacts/test_logs/basic-suite-master/post-004_basic_sanity.py/