Don't log missing pin file.

main.go

@@ -230,10 +230,7 @@ func main() {
 	}
 
 	// Check whether an authentification mechanism is pinned.
-	authMech, err := parsePinFile(user)
-	if err != nil {
-		log.Println("couldn't open authentification pin file:", err)
-	}
+	authMech, _ := parsePinFile(user)
 
 	// Set XMPP connection options.
 	options := xmpp.Options{