pgsql: Fix compiler warning

Fix compiler warning

With some newer gcc versions (8 and 9) you get a -Wformat-overflow
warning here. In PG11 and later this was already fixed. Since it's
trivial, backport it to get the older branches building without
warnings.

This back-patches commit 333a186dc into out-of-support branches,
pursuant to newly-established project policy. The point is to
suppress scary-looking warnings so that people building these
branches needn't expend brain cells verifying that it's safe
to ignore the warnings.

Discussion: https://postgr.es/m/d0316012-ece7-7b7e-2d36-9c38cb77cb3b@enterprisedb.com

Branch
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REL9_3_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/fcf1f27fe89bb017e5f05cc79bd640b96c6f7ba9

Modified Files
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contrib/pgbench/pgbench.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)