small fix to screenshot failures

Author: DavertMik

lib/plugin/screenshotOnFail.js

@@ -140,12 +140,8 @@ module.exports = function (config) {
   })
 
   function _getUUID(test) {
-    if (test.uuid) {
-      return test.uuid
-    }
-
-    if (test.ctx && test.ctx.test.uuid) {
-      return test.ctx.test.uuid
+    if (test.uid) {
+      return test.uid
     }
 
     return Math.floor(new Date().getTime() / 1000)