Fix grid.js typo

whats_open/static/js/grid.js

@@ -70,7 +70,7 @@ function update_grid(facilities) {
             // Special schedules take effect after 5am on their start day
             // to prevent collisions with the previous night's schedule, 
             // and they end at 5am the day after their end date.
-            special_start = Date.parse(special.vaild_start + ' 05:00:00');
+            special_start = Date.parse(special.valid_start + ' 05:00:00');
             special_end = Date.parse(special.valid_end  + ' 05:00:00');
             special_end.setDate(special_end.getDate()+1);
             if (now >= special_start && now <= special_end) {