Reenabling background services

--HG--
branch : 1.x

src/Orchard/Tasks/BackgroundService.cs

@@ -25,7 +25,6 @@ namespace Orchard.Tasks {
         public ILogger Logger { get; set; }
 
         public void Sweep() {
-            return;
             foreach(var task in _tasks.OfType<IBackgroundTask>()) {
                 using (var scope = new TransactionScope(TransactionScopeOption.RequiresNew)) {
                     try {