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
```