Don't allow pop3_uidl_format without at least one valid %var in it.
Don't allow pop3_uidl_format without at least one valid %var in it.

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