Updating example.js to match tutorial

example.js was out of sync with the tutorial; handleCommentSubmit does not need a call back.

public/scripts/example.js

@@ -40,23 +40,19 @@ var CommentBox = React.createClass({
   },
   handleCommentSubmit: function(comment) {
     var comments = this.state.data;
-    comments.push(comment);
-    this.setState({data: comments}, function() {
-      // `setState` accepts a callback. To avoid (improbable) race condition,
-      // we'll send the ajax request right after we optimistically set the new
-      // state.
-      $.ajax({
-        url: this.props.url,
-        dataType: 'json',
-        type: 'POST',
-        data: comment,
-        success: function(data) {
-          this.setState({data: data});
-        }.bind(this),
-        error: function(xhr, status, err) {
-          console.error(this.props.url, status, err.toString());
-        }.bind(this)
-      });
+    var newComments = comments.concat([comment]);
+    this.setState({data: newComments});
+    $.ajax({
+      url: this.props.url,
+      dataType: 'json',
+      type: 'POST',
+      data: comment,
+      success: function(data) {
+        this.setState({data: data});
+      }.bind(this),
+      error: function(xhr, status, err) {
+        console.error(this.props.url, status, err.toString());
+      }.bind(this)
     });
   },
   getInitialState: function() {