Fix(queryGenerator#quote): `as` variable

lib/dialects/abstract/query-generator.js

@@ -546,6 +546,7 @@ module.exports = (function() {
           var model, as;
           var model, as;
           if (item instanceof Model) {
           if (item instanceof Model) {
             model = item;
             model = item;
+            as = undefined;
           } else {
           } else {
             model = item.model;
             model = item.model;
             as = item.as;
             as = item.as;