Adding test helper to test private methods
Clear up confusion of log_rotate_size config value

Remove the second comment which could be confused with suggesting an invalid value: `// 100 MiB`.

To keep the easily readable example value, it has been moved into the comment header for the config item.
Merge pull request #11335 from danbartram/imp_logrotate_conf_example

Clear up confusion of log_rotate_size config value
Merge pull request #11322 from owncloud/adding-unittest-helper

Adding test helper to test private methods
[tx-robot] updated from transifex