hotfix for dovecot namespace on ubuntu 18.04

install/ubuntu/18.04/dovecot/conf.d/10-mail.conf

@@ -2,3 +2,8 @@ mail_privileged_group = mail
 mail_access_groups = mail
 mail_location = maildir:%h/mail/%d/%n
 pop3_uidl_format = %08Xu%08Xv
+namespace inbox {
+  inbox = yes
+}
+first_valid_uid = 1000
+mbox_write_locks = fcntl

install/ubuntu/18.04/dovecot/dovecot.conf

@@ -2,23 +2,3 @@ protocols = imap pop3
 listen = *, ::
 base_dir = /var/run/dovecot/
 !include conf.d/*.conf
-
-namespace inbox {
-    type = private
-    separator = /
-    prefix =
-    inbox = yes
-
-    mailbox Sent {
-        auto = subscribe
-        special_use = \Sent
-    }
-    mailbox Drafts {
-        auto = subscribe
-        special_use = \Drafts
-    }
-    mailbox Trash {
-        auto = subscribe
-        special_use = \Trash
-    }
-}