maildir: When noticing invalid 'S' in filename, replace it with the correct one instead of removing it.
maildir: When noticing invalid 'S' in filename, replace it with the correct one instead of removing it.

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