Properly handle dispose UI context.

Therzok · Therzok · commit fdaef70c331f · 2018-07-18T22:35:35.000+03:00
This is a hack, we need to fix mono#4751
diff --git a/main/src/addins/VersionControl/MonoDevelop.VersionControl/MonoDevelop.VersionControl/VersionControlTask.cs b/main/src/addins/VersionControl/MonoDevelop.VersionControl/MonoDevelop.VersionControl/VersionControlTask.cs
@@ -70,7 +70,8 @@ void BackgroundWorker ()
 		public void Wakeup() {
 			try {
 				tracker.EndTask();
-				tracker.Dispose();
+				// Remove this when https://github.com/mono/monodevelop/issue/4751 is fixed.
+				Runtime.MainSynchronizationContext.Post (o => ((ProgressMonitor)o).Dispose (), tracker);
 			} finally {
 				Finished();
 			}
