notification email on student unlinking

sails/src/api/controllers/StudentController.js

@@ -472,6 +472,7 @@ module.exports = {
         throw new Error("student and supervisor are not linked");
 
       return [stupStup, Student.findOne(req.params.id_stu).populate('license')];
+    })
     .spread((stuSup, student) => {
 
       //