[minor] change `max` TODO comment.

lib/winston-mongodb.js

@@ -37,8 +37,9 @@ var MongoDB = exports.MongoDB = function (options) {
   this.password     = options.password || null;
   this.errorTimeout = options.errorTimeout || 10000;
   this.capped       = options.capped;
-  // TODO: possibly go by docs (`max`) instead
   this.cappedSize   = options.cappedSize || 10000000;
+  // TODO: possibly go by docs (`max`) instead
+  // this.length       = options.length    || 200;
 
   if (options.keepAlive !== true) {
     //