use var instead of let

Author: bantic

lib/transforms/import-declarations.js

@@ -3,9 +3,9 @@ var path_utils = require('../utils/path');
 function transformer(file, api) {
   var j = api.jscodeshift;
 
-  let root = j(file.source);
+  var root = j(file.source);
 
-  let foundHelper;
+  var foundHelper;
 
   root.find(j.ImportDeclaration, {
     source: { value: '@ember/component/helper' },
@@ -14,7 +14,7 @@ function transformer(file, api) {
   })
   .forEach(function(path) {
     foundHelper = true;
-    let specifier = j.importSpecifier(j.identifier('helper'), j.identifier('buildHelper'));                              
+    var specifier = j.importSpecifier(j.identifier('helper'), j.identifier('buildHelper'));                              
 
     path.value.specifiers[0] = specifier;
   });