Updates keyboard handling to use keyCode

Author: claydiffrient

Diff for: lib/components/ModalPortal.js

@@ -97,8 +97,8 @@ var ModalPortal = module.exports = React.createClass({
   },
 
   handleKeyDown: function(event) {
-    if (event.key == 9 /*tab*/) scopeTab(this.getDOMNode(), event);
-    if (event.key == 27 /*esc*/) this.requestClose();
+    if (event.keyCode == 9 /*tab*/) scopeTab(this.getDOMNode(), event);
+    if (event.keyCode == 27 /*esc*/) this.requestClose();
   },
 
   handleOverlayClick: function() {