Set maildir as default format for mailboxes.

Till Brehm · Till Brehm · commit a585f9b154da · 2016-04-20T18:54:01.000+02:00
diff --git a/install/tpl/server.ini.master b/install/tpl/server.ini.master
@@ -32,6 +32,7 @@ monitor_system_updates=y
 module=postfix_mysql
 maildir_path=/var/vmail/[domain]/[localpart]
 homedir_path=/var/vmail
+maildir_format=maildir
 dkim_path=/var/lib/amavis/dkim
 dkim_strength=1024
 pop3_imap_daemon=courier
