pgsql: Fix unused-variable warning.

Fix unused-variable warning.

Discussion: /messages/by-id/CAMkU=1xTHkS6d0iptCWykHc1Xrh3LBic_gZDo3JzDYru815fLQ@mail.gmail.com

Branch
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REL_11_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/6f4e01c7d289ee39d08317f12ef979805bcbba00

Modified Files
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src/backend/executor/execExpr.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)