Exposing the watch_log from file-stream-rotator to allow the logfile to be recreated in case of accidental deletion

[chneil]

Related to issue: https://github.com/winstonjs/winston/issues/705

• Added new unit test to check for 'addWatcher' event - all unit tests green
• Fixed other unit tests "Error: done() called multiple times" by removing listeners after event
• Manual test: with watch_log=true, the logfile is recreated on deletion but only once since the watchers are not readded -- dependency on: https://github.com/rogerc/file-stream-rotator/pull/83 to allow continuous logfile deletion to be recreated

Reference:

• watch_log Watch the current file being written to and recreate it in case of accidental deletion. Defaults to 'FALSE'
• https://github.com/rogerc/file-stream-rotator/blob/d48e1ec847bd27bc7896462d0e56ba19f07c581e/FileStreamRotator.js#L58
• https://github.com/rogerc/file-stream-rotator/blob/d48e1ec847bd27bc7896462d0e56ba19f07c581e/FileStreamRotator.js#L552-L563

[chneil]

@mattberther Hey there, any way we can get a look at this PR? Let me know if it needs additional info.

Same if we can get a 👀 at https://github.com/rogerc/file-stream-rotator/pull/83

[mattberther]

Thank you for the contribution. Merged to master and published as winston-daily-rotate-file@4.6.0.