**Do you want to request a _feature_ or report a _bug_?**

This is a bug

**What is the current behavior?**

![screen shot 2016-07-03 at 4 12 19 pm](https://cloud.githubusercontent.com/assets/1697380/16544656/b3f896b2-4140-11e6-923a-06fc630c92df.png)
![screen shot 2016-07-03 at 4 11 15 pm](https://cloud.githubusercontent.com/assets/1697380/16544657/b3f8f292-4140-11e6-8b03-0ecaa3165460.png)

**If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal demo of the problem via https://jsfiddle.net or similar (template: https://jsfiddle.net/reactjs/69z2wepo/).**

Using 15.2.0 react and react-dom

**What is the expected behavior?**

![screen shot 2016-07-03 at 4 13 05 pm](https://cloud.githubusercontent.com/assets/1697380/16544659/b938951e-4140-11e6-9275-2c3721542003.png)
![screen shot 2016-07-03 at 4 13 10 pm](https://cloud.githubusercontent.com/assets/1697380/16544660/b9391278-4140-11e6-9951-0f81024ce859.png)

**Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?**

In 15.2.0, extra attributes `name` and `value` with empty values are added to the submit button of a form.

It works in 15.1.0.

constructor() {
          super();
          setValueToNull = () => this.setState({value: null});
        }
        state = {value: 'first'};
        render() {
          return (
            <input
              onChange={e => this.setState({value: e.target.value})}
              value={this.state.value}
            />
          );
        }
      }
      const stub = ReactDOM.render(<Input />, container);
      input = ReactDOM.findDOMNode(stub);
      setUntrackedValue.call(input, 'latest');
      dispatchEventOnNode(input, 'input');
      setValueToNull();
    }
    it('reverts the value attribute to the initial value', () => {
      expect(renderInputWithStringThenWithNull).toWarnDev([
        '`value` prop on `input` should not be null. ' +
          'Consider using an empty string to clear the component ' +