Use hasViewLoaded bool I found.

Author: ksuther

PBGitHistoryController.m

@@ -488,7 +488,7 @@ - (void)closeView
 	[treeController removeObserver:self forKeyPath:@"selection"];
 
 	//Only stop these observations if the nib got loaded
-	if ([self treeController]) {
+	if (hasViewLoaded) {
 		[repository.revisionList removeObserver:self forKeyPath:@"isUpdating"];
 		[repository removeObserver:self forKeyPath:@"currentBranch"];
 		[repository removeObserver:self forKeyPath:@"refs"];