Fix jsx-uses-vars to work better with prefer-const (fixes #716)

Author: yannickcr

lib/rules/jsx-uses-vars.js

@@ -23,13 +23,6 @@ module.exports = {
   create: function(context) {
 
     return {
-      JSXExpressionContainer: function(node) {
-        if (node.expression.type !== 'Identifier') {
-          return;
-        }
-        variableUtil.markVariableAsUsed(context, node.expression.name);
-      },
-
       JSXOpeningElement: function(node) {
         var name;
         if (node.name.namespace && node.name.namespace.name) {