Give nice error message for "SORT ()"
Give nice error message for "SORT ()"

--HG--
branch : HEAD

dscho/dovecot,jkerihuel/dovecot,jkerihuel/dovecot,jwm/dovecot-notmuch,jwm/dovecot-notmuch,jwm/dovecot-notmuch,jwm/dovecot-notmuch,jkerihuel/dovecot,jkerihuel/dovecot,jkerihuel/dovecot,dscho/dovecot,dscho/dovecot,dscho/dovecot,dscho/dovecot,jwm/dovecot-notmuch