function ModalHeader() {
	    (0, _classCallCheck3['default'])(this, ModalHeader);
	    return (0, _possibleConstructorReturn3['default'])(this, _React$Component.apply(this, arguments));
	  }
A Callback fired when the close button is clicked. If used directly inside
a Modal component, the onHide will automatically be propagated up to the
parent Modal `onHide`.