mappingstorage: fix sort_on in buildQuery

src/jio.storage/mappingstorage.js

@@ -399,7 +399,7 @@
       for (i = 0; i < option.sort_on.length; i += 1) {
         property = mapToMainProperty(this, option.sort_on[i][0], {}, {});
         if (property && sort_on.indexOf(property) < 0) {
-          select_list.push([property, option.sort_on[i][1]]);
+          sort_on.push([property, option.sort_on[i][1]]);
         }
       }
     }
@@ -407,7 +407,7 @@
       for (i = 0; i < this._query.sort_on.length; i += 1) {
         property = mapToMainProperty(this, this._query.sort_on[i], {}, {});
         if (sort_on.indexOf(property) < 0) {
-          select_list.push([property, option.sort_on[i][1]]);
+          sort_on.push([property, option.sort_on[i][1]]);
         }
       }
     }