create rum index without "WITH" cause an error when select use “ORDER BY”

[Wenbo94]

Use postgres REL_12_STABLE branch

postgres=# CREATE TABLE tsts (id int, t tsvector, d timestamp);
CREATE TABLE
postgres=# \copy tsts from '/rum/data/tsts.data'
COPY 508
postgres=# CREATE INDEX tsts_idx ON tsts USING rum (t rum_tsvector_addon_ops, d);
CREATE INDEX
postgres=# SELECT id, d, d <=> '2016-05-16 14:21:25' FROM tsts WHERE t @@ 'wr&qh' ORDER BY d <=> '2016-05-16 14:21:25' LIMIT 5;
ERROR: cannot order without attribute 2 in WHERE clause
postgres=# DROP INDEX tsts_idx;
DROP INDEX
postgres=# SELECT id, d, d <=> '2016-05-16 14:21:25' FROM tsts WHERE t @@ 'wr&qh' ORDER BY d <=> '2016-05-16 14:21:25' LIMIT 5;
id | d | ?column?
-----+----------------------------+---------------
355 | 2016-05-16 14:21:22.326724 | 2.673276
354 | 2016-05-16 13:21:22.326724 | 3602.673276
371 | 2016-05-17 06:21:22.326724 | 57597.326724
406 | 2016-05-18 17:21:22.326724 | 183597.326724
415 | 2016-05-19 02:21:22.326724 | 215997.326724
(5 rows)