pgsql: Clean up minor collation issues in indxpath.c.

Clean up minor collation issues in indxpath.c.

Get rid of bogus collation test in match_special_index_operator (even for
ILIKE, the pattern match operator's collation doesn't matter here, and even
if it did the test was testing the wrong thing).
Fix broken looping logic in expand_indexqual_rowcompare.
Add collation check in match_clause_to_ordering_op.
Make naming and argument ordering more consistent; improve comments.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/69f1d5fe1456229aeea3096c372eb24cedc7d597

Modified Files
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src/backend/optimizer/path/indxpath.c | 103 +++++++++++++++++++-------------
1 files changed, 61 insertions(+), 42 deletions(-)