doveadm backup: Fix to earlier commit - don't try to delete an already empty mailbox.
doveadm backup: Fix to earlier commit - don't try to delete an already empty mailbox.

LTD-Beget/dovecot,LTD-Beget/dovecot,LTD-Beget/dovecot,LTD-Beget/dovecot,LTD-Beget/dovecot