* Util/Scheduler.cs: Don't allow tasks to be added without a source
        * beagled/IndexSynchronization.cs: Fake a source for scheduler tasks

Index: Util/Scheduler.cs
===================================================================
RCS file: /cvs/gnome/beagle/Util/Scheduler.cs,v
retrieving revision 1.30
diff -u -B -p -r1.30 Scheduler.cs
--- Util/Scheduler.cs	15 Sep 2005 16:05:18 -0000	1.30
+++ Util/Scheduler.cs	6 Oct 2005 15:51:44 -0000
@@ -547,7 +547,10 @@ namespace Beagle.Util {
 		{
 			if (task == null)
 				return;
-			
+
+			if (task.Source == null)
+				throw new Exception ("Attempting to add Task with no source!");
+
 			Task old_task = null;
 
 			lock (big_lock) {
Index: beagled/IndexSynchronization.cs
===================================================================
RCS file: /cvs/gnome/beagle/beagled/IndexSynchronization.cs,v
retrieving revision 1.1
diff -u -B -p -r1.1 IndexSynchronization.cs
--- beagled/IndexSynchronization.cs	13 Jul 2005 16:28:40 -0000	1.1
+++ beagled/IndexSynchronization.cs	6 Oct 2005 15:51:45 -0000
@@ -68,12 +68,14 @@ namespace Beagle.Daemon {
 			task.Tag = "Synchronize Indexes";
 			task.Priority = Scheduler.Priority.Delayed;
 			task.TriggerTime = DateTime.Now.AddMinutes (sync_interval_in_minutes);
+			task.Source = synchronization_lock;
 			Scheduler.Global.Add (task);
 
 			// Set up the shutdown synchronization task
 			task = Scheduler.TaskFromHook (new Scheduler.TaskHook (ShutdownHook));
 			task.Tag = "Synchronize Indexes on Shutdown";
 			task.Priority = Scheduler.Priority.Shutdown;
+			task.Source = synchronization_lock;
 			Scheduler.Global.Add (task);
 		}