Fix pathToNode with a sibling node which has children

[koba04]

Currently, the following test is failed.

const wrapper = shallow(
  <div className="bax">
    <div className="foo">
      <div className="bar">
        <div className="baz" />
        <div>
          <div />
        </div>
      </div>
    </div>
  </div>
);

expect(wrapper.find('.baz').parent().hasClass('bar')).to.equal(true);

This is because pathToNode returns trees which are including the sibling node.
This PR makes pathToNode return only nodes including the current node.

Thanks

[lelandrichardson]

Thanks for helping out. This is a great fix.

Do you mind rebasing before I merge it in? Thanks!

[koba04]

@lelandrichardson Thank you! rebased.