Bug to apply migration if binlog is compressed.

Database Version: `10.2.25-MariaDB`
OS: `debian-linux-gnu`

The bug happens if the bank is set to save [compressed binlog](https://mariadb.com/kb/en/library/compressing-events-to-reduce-size-of-the-binary-log/). '
```
MariaDB [(none)]> show variables like 'log_bin_compress';
+------------------+-------+
| Variable_name | Value |
+------------------+-------+
| log_bin_compress | ON |
+------------------+-------+
```

Behavior:
The whole process happens correctly, but after the postponing file removal the following log occurs:

```
2019-11-13 17:53:21 INFO Grabbing voluntary lock: gh-ost.1276299.lock
2019-11-13 17:53:21 INFO Setting LOCK timeout as 6 seconds
2019-11-13 17:53:21 INFO Looking for magic cut-over table
2019-11-13 17:53:21 INFO Creating magic cut-over table `cifra`.`_songbook_log_del`
2019-11-13 17:53:21 INFO Magic cut-over table created
2019-11-13 17:53:21 INFO Locking `cifra`.`songbook_log`, `cifra`.`_songbook_log_del`
2019-11-13 17:53:22 INFO Tables locked
2019-11-13 17:53:22 INFO Session locking original & magic tables is 1276299
2019-11-13 17:53:22 INFO Writing changelog state: AllEventsUpToLockProcessed:1573667602084929375
2019-11-13 17:53:22 INFO Waiting for events up to lock
2019-11-13 17:53:25 ERROR Timeout while waiting for events up to lock
2019-11-13 17:53:25 ERROR 2019-11-13 17:53:25 ERROR Timeout while waiting for events up to lock
2019-11-13 17:53:25 INFO Looking for magic cut-over table
2019-11-13 17:53:25 INFO Will now proceed to drop magic table and unlock tables
2019-11-13 17:53:25 INFO Dropping magic cut-over table
2019-11-13 17:53:25 INFO Releasing lock from `cifra`.`songbook_log`, `cifra`.`_songbook_log_del`
2019-11-13 17:53:25 INFO Tables unlocked
```

El informe no proporciona ningún archivo fuente, prueba ni punto de entrada. Empieza reproduciendo la migración con MariaDB 10.2.25, Debian y log_bin_compress habilitado; después, rastrea el manejo de eventos del binlog comprimido de la migración en torno al timeout posterior al aplazamiento de la eliminación del archivo. Se considera completado cuando la migración finaliza sin el timeout indicado y una prueba de regresión cubre esta configuración.

Escrito por el modelo de indexación a partir del texto del issue.