pgsql: Fix OID passed to object-alter hook during ALTER CONSTRAINT

Fix OID passed to object-alter hook during ALTER CONSTRAINT

The OID of the constraint is used instead of the OID of the trigger --
an easy mistake to make.  Apparently the object-alter hooks are not very
well tested :-(

Backpatch to 12, where this typo was introduced by 578b229718e8

Discussion: https://postgr.es/m/20210503231633.GA6994@alvherre.pgsql

Branch
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REL_12_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/72fabd4bfb5a8189591933cf244eabcaf83d4b8b

Modified Files
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src/backend/commands/tablecmds.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)