pg_dump: Remove stray option parsing support for -o.

I (Andres) missed this in 578b2297, the removal of WITH OIDS
support.

Author: Daniel Verite
Discussion: https://postgr.es/m/f06e9735-3717-4904-8c95-47d0b9c3bb10@manitou-mail.org

src/bin/pg_dump/pg_dump.c

@@ -428,7 +428,7 @@ main(int argc, char **argv)
 
 	InitDumpOptions(&dopt);
 
-	while ((c = getopt_long(argc, argv, "abBcCd:E:f:F:h:j:n:N:oOp:RsS:t:T:U:vwWxZ:",
+	while ((c = getopt_long(argc, argv, "abBcCd:E:f:F:h:j:n:N:Op:RsS:t:T:U:vwWxZ:",
 							long_options, &optindex)) != -1)
 	{
 		switch (c)