isolate: manage lifetime of checker and uploader in main.

client/cmd/isolate/upload_tracker.go

Index: client/cmd/isolate/upload_tracker.go
diff --git a/client/cmd/isolate/upload_tracker.go b/client/cmd/isolate/upload_tracker.go
index 8ff7fe4ed386e9ce9383ccb55c9101bc9e789e6d..44f00c89fd8d9397e85f9fdb9bfd7ee673918dff 100644
--- a/client/cmd/isolate/upload_tracker.go
+++ b/client/cmd/isolate/upload_tracker.go
@@ -197,16 +197,6 @@ func (ut *UploadTracker) Finalize(isolatedPath string) (IsolatedSummary, error)
 		})
 	})
 
-	// Make sure that all pending items have been checked.
-	if err := ut.checker.Close(); err != nil {
-		return IsolatedSummary{}, err
-	}
-
-	// Make sure that all the uploads have completed successfully.
-	if err := ut.uploader.Close(); err != nil {
-		return IsolatedSummary{}, err
-	}
-
 	// Write the isolated file...
 	if err := isolFile.writeJSONFile(ut.lOS); err != nil {
 		return IsolatedSummary{}, err