pgsql: Fix typo in test

Fix typo in test

The test was supposed to error but didn't.  Apparently, a copy and
paste and string replace mistake from a nearby similar test.

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/bae9e8a58bf642aa383f5dc01b2c5947bae533dd

Modified Files
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src/test/modules/unsafe_tests/expected/rolenames.out | 5 ++++-
src/test/modules/unsafe_tests/sql/rolenames.sql      | 2 +-
2 files changed, 5 insertions(+), 2 deletions(-)