Reattach 'readable' event listener when changing streams

Parser was not unregistering the 'readable' event listener from the old
socket, nor registering it to the new socket when setSocket() was
called.  This caused event handling to stop during the STARTTLS handoff.

Signed-off-by: Kevin Locke <klocke@quantpost.com>

lib/Parser.js

@@ -40,8 +40,6 @@ function Parser(stream, debug) {
   this._ignoreReadable = false;
   this.debug = debug;
 
-  this.setStream(stream);
-
   var self = this;
   this._cbReadable = function() {
     if (self._ignoreReadable)
@@ -51,12 +49,18 @@ function Parser(stream, debug) {
     else
       self._tryread();
   };
-  this._stream.on('readable', this._cbReadable);
+
+  this.setStream(stream);
+
   process.nextTick(this._cbReadable);
 }
 inherits(Parser, EventEmitter);
 
 Parser.prototype.setStream = function(stream) {
+  if (this._stream) {
+    this._stream.removeListener('readable', this._cbReadable);
+  }
+
   if (/^v0\.8\./.test(process.version)) {
     this._stream = (new ReadableStream()).wrap(stream);
 
@@ -66,6 +70,8 @@ Parser.prototype.setStream = function(stream) {
     stream._events.error.pop();
   } else
     this._stream = stream;
+
+  this._stream.on('readable', this._cbReadable);
 };
 
 Parser.prototype._tryread = function(n) {