pgsql: Fix incorrect usage of non-strict OR joinclauses in appendrel in

Fix incorrect usage of non-strict OR joinclauses in appendrel indexscans.

By chance I happened to notice that bug #5076 was still broken in the
8.3 branch, though it worked everywhere else.  The reason is that 8.3's
version of adjust_appendrel_attrs_mutator neglected to adjust
RestrictInfo.nullable_relids.  This was an oversight in my patch of
2009-04-16, which I apparently corrected in the later branches on
2009-08-13 without realizing that it affected the 8.3 branch as well.
By the time the bug report was filed, it was not reproducible in 8.4.
I don't recall if I wrote it off as already fixed, or it just fell through
the cracks; but anyway it's been a live bug in 8.3 for a year.

Branch
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REL8_3_STABLE

Details
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http://git.postgresql.org/gitweb?p=postgresql.git;a=commitdiff;h=a2e26a6f888a91da7efd7f59ca5d9b9383f2edd1

Modified Files
--------------
src/backend/optimizer/prep/prepunion.c |    3 +++
1 files changed, 3 insertions(+), 0 deletions(-)