pgsql: Avoid assuming that we know the spelling of getopt_long'serror

Avoid assuming that we know the spelling of getopt_long's error messages.

I've had enough of "fixing" this test case.  Whatever value it has
is limited to verifying that pgbench fails for an unrecognized switch,
and we don't need to assume anything about what getopt_long prints in
order to do that.

Discussion: https://postgr.es/m/9427.1547701450@sss.pgh.pa.us

Branch
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REL_11_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/43404015955804dd6ff10563f4f78f5f352dbe25

Modified Files
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src/bin/pgbench/t/002_pgbench_no_server.pl | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)