pgsql: Fix DROP INDEX CONCURRENTLY IF EXISTS.

Fix DROP INDEX CONCURRENTLY IF EXISTS.

This threw ERROR, not the expected NOTICE, if the index didn't exist.
The bug was actually visible in not-as-expected regression test output,
so somebody wasn't paying too close attention in commit
8cb53654dbdb4c386369eb988062d0bbb6de725e.
Per report from Brendan Byrd.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/e323c553017601597b6a5f9f19426587df512ad9

Modified Files
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src/backend/parser/gram.y | 2 +-
src/test/regress/expected/create_index.out | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)