pgbench: Move constant into format string

As coded, the row data strings generated for pgbench_accounts' COPY in
the client-side data generation were always assigning 0 for one of its
attributes.  This simplifies a bit an upcoming patch to switch
client-side data generation of pgbench to use COPY for the teller and
branch tables, rather than individual INSERTs.

Author: Tristan Partin
Discussion: https://postgr.es/m/CSTU5P82ONZ1.19XFUGHMXHBRY@c3po

Author: michaelpq

src/bin/pgbench/pgbench.c

@@ -4947,8 +4947,8 @@ initGenerateDataClientSide(PGconn *con)
 
 		/* "filler" column defaults to blank padded empty string */
 		printfPQExpBuffer(&sql,
-						  INT64_FORMAT "\t" INT64_FORMAT "\t%d\t\n",
-						  j, k / naccounts + 1, 0);
+						  INT64_FORMAT "\t" INT64_FORMAT "\t0\t\n",
+						  j, k / naccounts + 1);
 		if (PQputline(con, sql.data))
 			pg_fatal("PQputline failed");