mdbox: Don't hoard file descriptors when saving mails that are larger than mdbox_rotate_size.
mdbox: Don't hoard file descriptors when saving mails that are larger than mdbox_rotate_size.

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