Return false from the timeout callback function

Timeout callback function should not be rescheduled again with the same timeout
because we compute a new timeout and schedule it again instead. So the callback
function needs to return false to not be scheduled again by default.

js/ui/docDisplay.js

@@ -224,7 +224,7 @@ DocDisplay.prototype = {
             docDisplayItem.redisplay(currentSecs);          
             this._updateTimeoutCallback(docDisplayItem, currentSecs);
         }
-        return true;
+        return false;
     },
 
     // Updates the timeout callback if the timeout time for the docDisplayItem