add the missing space. in the future, should mail -f the file to ensure it is correct format

src/etc/root/root.mail

@@ -1,4 +1,4 @@
-From deraadt@do-not-reply.openbsd.org Sun Nov 1 06:30:00 MDT 2018
+From deraadt@do-not-reply.openbsd.org Sun Nov  1 06:30:00 MDT 2018
 Return-Path: root
 Date: Nov 1 06:30:00 MDT 2018
 From: deraadt@do-not-reply.openbsd.org (Theo de Raadt)