Transactional test on zSeries contains wrong LSN in checkpoint

FAIL: test_txn04.test_txn04.test_ops(fix.update.t1r) (subunit.RemotedTestCase)

test_txn04.test_txn04.test_ops(fix.update.t1r)

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_StringException: Traceback (most recent call last):

  File "/mnt/workspace/wiredtiger-test-unit-zseries/test/suite/test_txn04.py", line 191, in test_ops

    self.ops()

  File "/mnt/workspace/wiredtiger-test-unit-zseries/test/suite/test_txn04.py", line 139, in ops

    self.hot_backup(None, committed)

  File "/mnt/workspace/wiredtiger-test-unit-zseries/test/suite/test_txn04.py", line 114, in hot_backup

    self.runWt(cmd.split())

  File "/mnt/workspace/wiredtiger-test-unit-zseries/test/suite/suite_subprocess.py", line 200, in runWt

    str(procargs) + '": exited ' + str(returncode))

  File "/usr/lib64/python2.7/unittest/case.py", line 553, in assertEqual

    assertion_func(first, second, msg=msg)

  File "/usr/lib64/python2.7/unittest/case.py", line 546, in _baseAssertEqual

    raise self.failureException(msg)

AssertionError: expected success: "['/mnt/workspace/wiredtiger-test-unit-zseries/build_posix/wt', '-h', '.', 'backup', './WT_BACKUP']": exited 1