databases/cego: update 2.33.19 -> 2.33.20

Fix in CegoDistCursor to support advanced left and right outer
join queries of the form

SELECT tx.a AS xa, ty.a AS ya FROM t1 tx
LEFT OUTER JOIN t2 ty ON tx.a = ty.a + 1;

For this, the evaluation of the predicate has to be done in a
different way to get complete row set

Submitted by: Bjoern Lemke <lemke@lemke-it.com>