fix panic when there were no recent errors

reflector/stats.go

@@ -102,8 +102,10 @@ func (s *stats) log() {
 		delete(s.errors, name)
 	}
 	s.mu.Unlock()
-	s.logger.Printf(
-		"Stats: %d blobs, %d streams, errors: %s",
-		blobs, streams, errStr[:len(errStr)-2], // trim last comma and space
-	)
+
+	if len(errStr) > 2 {
+		errStr = errStr[:len(errStr)-2] // trim last comma and space
+	}
+
+	s.logger.Printf("Stats: %d blobs, %d streams, errors: %s", blobs, streams, errStr)
 }

updater/updater.go

@@ -15,8 +15,9 @@ import (
 // TODO: this needs to be shut down cleanly
 
 func Run(url, updateCmd string) {
+	t := time.NewTicker(1 * time.Minute)
 	for {
-		<-time.After(1 * time.Minute)
+		<-t.C
 
 		r, err := http.Head(url)
 		if err != nil {