transport-helper.c: do not translate a string twice

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/transport-helper.c b/transport-helper.c
index 84a1066..7bd16c4 100644
--- a/transport-helper.c
+++ b/transport-helper.c
@@ -573,7 +573,7 @@
 			fprintf(stderr, "Debug: Falling back to dumb "
 				"transport.\n");
 	} else {
-		die(_(_("unknown response to connect: %s")),
+		die(_("unknown response to connect: %s"),
 		    cmdbuf->buf);
 	}