Log Message:
-----------
Fix build_minmax_path() to cope if an IS NULL clause turns up in the
indexable-clauses list for a btree index. Formerly it just Asserted that
all such clauses were opclauses, but that's no longer true in 8.3.
Per bug #3796 from Matthias Schoeneich.
Modified Files:
--------------
pgsql/src/backend/optimizer/plan:
planagg.c (r1.34 -> r1.35)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/optimizer/plan/planagg.c?r1=1.34&r2=1.35)