pgsql: Fix pg_dump's failure to dump REPLICA IDENTITY for constraint in

Fix pg_dump's failure to dump REPLICA IDENTITY for constraint indexes.

pg_dump knew about printing ALTER TABLE ... REPLICA IDENTITY USING INDEX
for indexes declared as indexes, but it failed to print that for indexes
declared as unique or primary-key constraints. Per report from Achilleas
Mantzios.

This has been broken since the feature was introduced, AFAICS.
Back-patch to 9.4.

Discussion: https://postgr.es/m/1e6cc5ad-b84a-7c07-8c08-a4d0c3cdc938@matrix.gatewaynet.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/c0a552921b0f5f22ac982b5ad24f1df4fd8ca1b1

Modified Files
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src/bin/pg_dump/pg_dump.c | 26 ++++++++++++++++++++++++--
1 file changed, 24 insertions(+), 2 deletions(-)