Update .eslintrc.json

Enforce ES5 for tests

js/tests/unit/.eslintrc.json

@@ -2,34 +2,30 @@
   "extends": [
     "../../../.eslintrc.json"
   ],
-  "overrides": [
-    {
-      "files": [
-        "*.js"
-      ],
-      "env": {
-        "es6": false,
-        "jquery": true,
-        "qunit": true
-      },
-      "globals": {
-        "bootstrap": false,
-        "sinon": false,
-        "Util": false,
-        "Alert": false,
-        "Button": false,
-        "Carousel": false,
-        "Simulator": false,
-        "Toast": false
-      },
-      "rules": {
-        // ES6
-        "no-var": "off",
-        "object-shorthand": "off",
-        "prefer-arrow-callback": "off",
-        "prefer-template": "off",
-        "prefer-rest-params": "off"
-      }
-    }
-  ]
+  "parserOptions": {
+    "ecmaVersion": 5,
+    "sourceType": "script"
+  },
+  "env": {
+    "es6": false,
+    "jquery": true,
+    "qunit": true
+  },
+  "globals": {
+    "bootstrap": false,
+    "sinon": false,
+    "Util": false,
+    "Alert": false,
+    "Button": false,
+    "Carousel": false,
+    "Simulator": false,
+    "Toast": false
+  },
+  "rules": {
+    "no-var": "off",
+    "object-shorthand": "off",
+    "prefer-arrow-callback": "off",
+    "prefer-template": "off",
+    "prefer-rest-params": "off"
+  }
 }