pgsql: Fix lo_export usage in example programs.

Fix lo_export usage in example programs.

lo_export returns -1, not zero, on failure.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/f52c5165e1d067ba94f92e5f149c19109b6fed60

Modified Files
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src/test/examples/testlo.c | 2 +-
src/test/examples/testlo64.c | 4 ++--
2 files changed, 3 insertions(+), 3 deletions(-)