added small fix to prevent server from crashing on empty this.state

Author: Nicholas Moschopoulos

lib/Receiver.js

@@ -219,6 +219,7 @@ Receiver.prototype.processPacket = function (data) {
  */
 
 Receiver.prototype.endPacket = function() {
+  if (this.dead) return;
   if (!this.state.fragmentedOperation) this.unfragmentedBufferPool.reset(true);
   else if (this.state.lastFragment) this.fragmentedBufferPool.reset(false);
   this.expectOffset = 0;