fast-export: improve argument parsing

We don't want to pass arguments specific to fast-export to
setup_revisions.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/fast-export.c

@@ -701,8 +701,9 @@ int cmd_fast_export(int argc, const char **argv, const char *prefix)
 	revs.topo_order = 1;
 	revs.show_source = 1;
 	revs.rewrite_parents = 1;
+	argc = parse_options(argc, argv, prefix, options, fast_export_usage,
+			PARSE_OPT_KEEP_ARGV0 | PARSE_OPT_KEEP_UNKNOWN);
 	argc = setup_revisions(argc, argv, &revs, NULL);
-	argc = parse_options(argc, argv, prefix, options, fast_export_usage, 0);
 	if (argc > 1)
 		usage_with_options (fast_export_usage, options);