python:tests: Make sure we delete the OU for movetest

python:tests: Make sure we delete the OU for movetest

UNEXPECTED(failure): samba.tests.samba_tool.group.samba.tests.samba_tool.group.GroupCmdTestCase.test_move(ad_dc_default:local)
REASON: Exception: Exception: Traceback (most recent call last):
  File "python/samba/tests/samba_tool/group.py", line 341, in test_move
    self.assertCmdSuccess(result, out, err)
  File "python/samba/tests/samba_tool/base.py", line 97, in assertCmdSuccess
    self.assertIsNone(exit, msg=msg.replace("\n]\n", "\n] \n"))
AssertionError: -1 is not None : exit[-1] stdout[] stderr[ERROR(ldb): Failed to
  add ou "OU=movetest,DC=addom,DC=samba,DC=example,DC=com" - Entry
  OU=movetest,DC=addom,DC=samba,DC=example,DC=com already exists

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15308

Signed-off-by: Andreas Schneider <asn@samba.org>
Reviewed-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
(cherry picked from commit a4307072d6ea5ddef5b37aa361e9e9f16f7254e7)