removed extraneous captureException

frontend/src/download.js

@@ -144,7 +144,7 @@ $(document).ready(function() {
           $('#download-btn').attr('hidden', true);
           $('#expired-img').removeAttr('hidden');
         }
-        return;
+        throw err;
       })
       .then(([decrypted, fname]) => {
         const endTime = Date.now();

frontend/src/fileSender.js

@@ -133,10 +133,6 @@ class FileSender extends EventEmitter {
           );
           xhr.send(fd);
         });
-      })
-      .catch(err => {
-        Raven.captureException(err);
-        return Promise.reject(err);
       });
   }
 }