Destroys the socket on error instead of end.

When only calling socket.end(), the socket would still respond to timeout
events.

lib/portscanner.js

@@ -68,7 +68,7 @@ portscanner.checkPortStatus = function(port, host, callback) {
   // Assuming the port is not open if an error. May need to refine based on
   // exception
   socket.on('error', function(exception) {
-    socket.end()
+    socket.destroy()
     callback(null, 'closed')
   })