add autocomplete guards

app/assets/javascripts/autocomplete.js

@@ -23,9 +23,12 @@
     if (this.enable_local_storage) {
       var now = new Date().getTime();
       $.each($.localStorage.keys(), function(i, key) {
-        var expiry = Date.parse($.localStorage.get(key));
-        if (expiry < now) {
-          $.localStorage.remove(key);
+        var obj = $.localStorage.get(key);
+        if (obj && obj.expires) {
+          var expiry = Date.parse(obj.expires);
+          if (expiry < now) {
+            $.localStorage.remove(key);
+          }          
         }
       });