style: fix lint

Author: vkarpov15

test/model.populate.test.js

@@ -4257,17 +4257,11 @@ describe('model: populate:', function() {
       });
 
       it('catchable error if localField or foreignField not specified (gh-6767)', function() {
-        const PersonSchema = new Schema({
-          name: String,
-          band: String
-        });
-
         const BandSchema = new Schema({
           name: String
         });
         BandSchema.virtual('members');
 
-        const Person = db.model('gh6767_Person', PersonSchema);
         const Band = db.model('gh6767_Band', BandSchema);
 
         return Band.create({ name: 'Motley Crue' }).