Emit 'logRemoved' event for files which are removed from disk

[RopoMen]

Currently this library is not emitting logRemoved event for files inside Audit JSON which are actually deleted from disk.

This causes issues for example in winston-daily-rotate-file which is providing gzip functionality and it compresses the original log files and then removes them from disk.

Now, because this remove event is not emitted winston-daily-rotate-file cannot delete those .gz files.

It is safe to emit this event because original log file is deleted. Whether deletion is done by file-stream-rotator or someone else.

[chrisstoy]

Is this ever going to be merged? Without this, winston-daily-rotate-file is essentially broken.

[rogerc]

The library emits the deleted file event when it is itself that deleted the file. If someone or something else deleted or renamed the file directly on disk, I won't notify of an external change, it will just remove the line from the audit log.

Does the gzip Winston library rename the file when zipped? If it does, the gzip library should handle its own audit log and delete accordingly.

I can look at adding a new event to notify that file was removed by 3rd party from disk, for completeness if someone wants to keep track of that.