streams2: Remove extraneous bufferSize setting

lib/_stream_readable.js

@@ -32,9 +32,6 @@ util.inherits(Readable, Stream);
 function ReadableState(options, stream) {
   options = options || {};
 
-  // cast to an int
-  this.bufferSize = ~~this.bufferSize;
-
   // the argument passed to this._read(n,cb)
   this.bufferSize = options.hasOwnProperty('bufferSize') ?
       options.bufferSize : 16 * 1024;