tests failing to mock logging (again)

[Amrith Kumar]

Error saving backup: 123.
Traceback (most recent call last):
  File "trove/guestagent/backup/backupagent.py", line 81, in stream_backup_to_storage
    **parent_metadata) as bkup:
  File "trove/guestagent/strategies/backup/mysql_impl.py", line 100, in __init__
    raise AttributeError('lsn attribute missing, bad parent?')
AttributeError: lsn attribute missing, bad parent?
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Unhandled message logged from backup.test_backupagent.BackupAgentTest.test_backup_incremental_bad_metadata, trove.guestagent.backup.backupagent
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Error saving backup: 123.
Traceback (most recent call last):
  File "trove/guestagent/backup/backupagent.py", line 111, in stream_backup_to_storage
    return meta
  File "trove/guestagent/strategies/backup/base.py", line 93, in __exit__
    raise BackupError
BackupError
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Unhandled message logged from backup.test_backupagent.BackupAgentTest.test_execute_bad_process_backup, trove.guestagent.backup.backupagent
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