fix EventEmitter memory leak

[bricewge]

On some torrents, after resuming, webtorrent-cli throw this warning:

(node:13649) MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 ready listeners added. Use emitter.setMaxListeners() to increase limit
    at _addListener (events.js:188:19)
    at Torrent.addListener (events.js:205:10)
    at Torrent.once (events.js:236:8)
    at Request.onChunk [as callback] (/home/bricewge/tmp/webtorrent-cli/node_modules/webtorrent/lib/torrent.js:1504:34)
    at Wire._callback (/home/bricewge/tmp/webtorrent-cli/node_modules/bittorrent-protocol/index.js:608:11)
    at Wire._onPiece (/home/bricewge/tmp/webtorrent-cli/node_modules/bittorrent-protocol/index.js:512:8)
    at Wire._onMessage (/home/bricewge/tmp/webtorrent-cli/node_modules/bittorrent-protocol/index.js:678:19)
    at Wire._write (/home/bricewge/tmp/webtorrent-cli/node_modules/bittorrent-protocol/index.js:596:10)
    at doWrite (/home/bricewge/tmp/webtorrent-cli/node_modules/readable-stream/lib/_stream_writable.js:428:64)
    at writeOrBuffer (/home/bricewge/tmp/webtorrent-cli/node_modules/readable-stream/lib/_stream_writable.js:417:5)

This PR seems to fix that.

It's related to #1122 and webtorrent/webtorrent-cli/issues/55.

[feross]

FYI, that warning is harmless, if annoying.

Honestly, I have no idea what the removed line does, hence the TODO. I'd need to re-read the code to make sure this won't break anything. We could also just merge it and see if there are new errors related to this in the WebTorrent Desktop telemetry.

[DiegoRBaquero]

The line if just deferring the chunk management until Torrent fires ready. So if over 10 chunks get downloaded before the Torrent fires ready, warning will be shown.

But... do we really care if torrent is not ready to store the chunk and mark the piece received, etc? Apparently not. I would just remove it.

@feross

[DiegoRBaquero]

This need to be fixed by correctly organizing the methods and events.